diff --git a/src/main/java/com/rackspace/cloud/api/docs/ApiRefMojo.java b/src/main/java/com/rackspace/cloud/api/docs/ApiRefMojo.java
index 9bcfbcd..b92d156 100644
--- a/src/main/java/com/rackspace/cloud/api/docs/ApiRefMojo.java
+++ b/src/main/java/com/rackspace/cloud/api/docs/ApiRefMojo.java
@@ -68,7 +68,7 @@ public abstract class ApiRefMojo extends AbstractHtmlMojo {
         String pathToPipelineFile = "classpath:/wadl2html.xpl"; //use "classpath:/path" for this to work
         Source source = super.createSource(inputFilename, sourceFile, filter);
 
-        Map map=new HashMap<String, String>();
+        Map<String, Object> map = new HashMap<String, Object>();
         
         map.put("security", security);
         map.put("canonicalUrlBase", canonicalUrlBase);
diff --git a/src/main/java/com/rackspace/cloud/api/docs/CalabashHelper.java b/src/main/java/com/rackspace/cloud/api/docs/CalabashHelper.java
index 3c14ab3..b3b9e9e 100644
--- a/src/main/java/com/rackspace/cloud/api/docs/CalabashHelper.java
+++ b/src/main/java/com/rackspace/cloud/api/docs/CalabashHelper.java
@@ -10,16 +10,17 @@ import javax.xml.transform.Source;
 import javax.xml.transform.sax.SAXSource;
 
 import java.io.ByteArrayInputStream;
+import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.InputStream;
+import java.net.URI;
+import java.net.URL;
 import java.util.ArrayList;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 
 public class CalabashHelper {
-    private static Source run(final String pipelineURI, final InputSource inputSource, final Map<String, String>map) throws FileNotFoundException {
+    private static Source run(final String pipelineURI, final InputSource inputSource, final Map<String, Object> map) throws FileNotFoundException {
         Pipeline pipeline = new CalabashPipelineBuilder(false, true).build(pipelineURI);
 
 //        <c:param-set xmlns:c="http://www.w3.org/ns/xproc-step">
@@ -33,17 +34,30 @@ public class CalabashHelper {
         
         
         if(null!=map){
-        	Set<String>keys=map.keySet();
-        	if(null!=keys){
-        		
-        	    for(Iterator<String>iter=keys.iterator();iter.hasNext();){
-        	    	String aKey=iter.next();
-        	    	if(null!=map.get(aKey)){	    	
-        	    	    strBuff.append("<c:param name=\""+aKey+ "\" namespace=\"\" value=\""+map.get(aKey)+"\"/>");
-        	    	}
-        	    }
-        	}
+            for (Map.Entry<String, Object> entry : map.entrySet()) {
+                String rawValue;
+                if (entry.getValue() instanceof File) {
+                    rawValue = ((File)entry.getValue()).toURI().toString();
+                } else if (entry.getValue() instanceof URI || entry.getValue() instanceof String) {
+                    rawValue = entry.getValue().toString();
+                } else if (entry.getValue() instanceof URL) {
+                    rawValue = ((URL)entry.getValue()).toExternalForm();
+                } else if (entry.getValue() != null) {
+                    throw new UnsupportedOperationException(String.format("The map cannot contain values of type %s.", entry.getValue().getClass()));
+                } else {
+                    // ignore nulls
+                    continue;
+                }
+
+                strBuff
+                    .append("<c:param name=\"")
+                    .append(entry.getKey())
+                    .append("\" namespace=\"\" value=\"")
+                    .append(rawValue)
+                    .append("\"/>");
+            }
         }
+
         strBuff.append("</c:param-set>");
         String params=strBuff.toString();
         final InputStream paramsStream = new ByteArrayInputStream(params.getBytes());
@@ -60,7 +74,27 @@ public class CalabashHelper {
         return sources.get(0);
     }
 
-    public static Source createSource(Source source, String pipelineURI, Map<String, String> map)
+    /**
+     * Creates a {@link Source} for use in a Calabash pipeline.
+     *
+     * <p>The {@code map} values may instances of {@link String}, {@link File},
+     * {@link URI}, or {@link URL}.</p>
+     *
+     * <ul>
+     * <li>{@link String}: These are passed to the pipeline unchanged.</li>
+     * <li>{@link URI}: The results of {@link URI#toString()} is passed to the pipeline.</li>
+     * <li>{@link File}: These are treated as URIs by calling {@link File#toURI()}.</li>
+     * <li>{@link URL}: The result of {@link URL#toExternalForm()} is passed to the pipeline.</li>
+     * <li>{@code null}: This is passed to the pipeline as an empty string.</li>
+     * </ul>
+     *
+     * @param source
+     * @param pipelineURI
+     * @param map
+     * @return
+     * @throws MojoExecutionException 
+     */
+    public static Source createSource(Source source, String pipelineURI, Map<String, Object> map)
             throws MojoExecutionException {
 
         try {
diff --git a/src/main/java/com/rackspace/cloud/api/docs/PDFMojo.java b/src/main/java/com/rackspace/cloud/api/docs/PDFMojo.java
index 5531448..461d350 100644
--- a/src/main/java/com/rackspace/cloud/api/docs/PDFMojo.java
+++ b/src/main/java/com/rackspace/cloud/api/docs/PDFMojo.java
@@ -533,7 +533,7 @@ public abstract class PDFMojo extends AbstractFoMojo {
 	Source source = new SAXSource(filter, inputSource);
         //Source source = super.createSource(inputFilename, sourceFile, filter);
 
-        Map map=new HashMap<String, String>();
+        Map<String, Object> map=new HashMap<String, Object>();
 	    String sysSecurity=System.getProperty("security");
 	    getLog().info("adjustTransformer():sysSecurity="+sysSecurity);
 	    if(null!=sysSecurity && !sysSecurity.isEmpty()){
diff --git a/src/main/java/com/rackspace/cloud/api/docs/WebHelpMojo.java b/src/main/java/com/rackspace/cloud/api/docs/WebHelpMojo.java
index 2bf70be..03de96e 100644
--- a/src/main/java/com/rackspace/cloud/api/docs/WebHelpMojo.java
+++ b/src/main/java/com/rackspace/cloud/api/docs/WebHelpMojo.java
@@ -754,7 +754,7 @@ public abstract class WebHelpMojo extends AbstractWebhelpMojo {
 	Source source = new SAXSource(filter, inputSource);
 	//Source source = super.createSource(inputFilename, sourceFile, filter);
 
-        Map<String, String> map=new HashMap<String, String>();
+        Map<String, Object> map = new HashMap<String, Object>();
         
         
         String sysWebhelpWar=System.getProperty("webhelp.war");
diff --git a/src/main/java/com/rackspace/cloud/api/docs/XhtmlMojo.java b/src/main/java/com/rackspace/cloud/api/docs/XhtmlMojo.java
index f7772e1..4b4c0b3 100644
--- a/src/main/java/com/rackspace/cloud/api/docs/XhtmlMojo.java
+++ b/src/main/java/com/rackspace/cloud/api/docs/XhtmlMojo.java
@@ -292,7 +292,7 @@ public abstract class XhtmlMojo extends AbstractHtmlMojo {
         String pathToPipelineFile = "classpath:/war.xpl"; //use "classpath:/path" for this to work
         Source source = super.createSource(inputFilename, sourceFile, filter);
 
-        Map map=new HashMap<String, String>();
+        Map<String, Object> map=new HashMap<String, Object>();
         
         map.put("failOnValidationError", failOnValidationError);
         map.put("transform.dir", transformDir);        
diff --git a/src/main/java/com/rackspace/cloud/api/docs/builders/PDFBuilder.java b/src/main/java/com/rackspace/cloud/api/docs/builders/PDFBuilder.java
index 68fdd2f..0e086a6 100644
--- a/src/main/java/com/rackspace/cloud/api/docs/builders/PDFBuilder.java
+++ b/src/main/java/com/rackspace/cloud/api/docs/builders/PDFBuilder.java
@@ -167,7 +167,7 @@ public class PDFBuilder {
 		FileUtils.extractJaredDirectory("fonts",PDFBuilder.class,imageParentDirectory);
 	}
 
-	public File processSources(Map<String,String> map) throws MojoExecutionException{
+	public File processSources(Map<String, Object> map) throws MojoExecutionException {
 		final String[] included = scanIncludedFiles();
 		// configure a resolver for catalog files
 		final CatalogManager catalogManager = createCatalogManager();
@@ -1063,7 +1063,7 @@ public class PDFBuilder {
 		return filter;
 	}
 
-	protected Source createSource(String inputFilename, File sourceFile, PreprocessingFilter filter, Map<String,String> map)
+	protected Source createSource(String inputFilename, File sourceFile, PreprocessingFilter filter, Map<String, Object> map)
 			throws MojoExecutionException {
 		String pathToPipelineFile = "classpath:/pdf.xpl"; //use "classpath:/path" for this to work
 
@@ -1072,7 +1072,7 @@ public class PDFBuilder {
 		final InputSource inputSource = new InputSource(sourceFileNameNormalized);
 		Source source = new SAXSource(filter, inputSource);
 
-		Map<String,String> localMap = new HashMap<String,String>(map); 
+		Map<String, Object> localMap = new HashMap<String, Object>(map);
 		localMap.put("outputType", "pdf");
 
 		//removing webhelp specific settings from map