diff --git a/pmd/src/net/sourceforge/pmd/SimpleRuleSetNameMapper.java b/pmd/src/net/sourceforge/pmd/SimpleRuleSetNameMapper.java
index 42140ee038..6e90cca107 100644
--- a/pmd/src/net/sourceforge/pmd/SimpleRuleSetNameMapper.java
+++ b/pmd/src/net/sourceforge/pmd/SimpleRuleSetNameMapper.java
@@ -7,7 +7,7 @@ import java.util.StringTokenizer;
 public class SimpleRuleSetNameMapper {
 
     private StringBuffer rulesets = new StringBuffer();
-    private Map<String, String> nameMap = new HashMap<String, String>();
+    protected Map<String, String> nameMap = new HashMap<String, String>();
 
     public SimpleRuleSetNameMapper(String ruleString) {
         populateNameMap();
@@ -25,7 +25,7 @@ public class SimpleRuleSetNameMapper {
         return rulesets.toString();
     }
 
-    private void check(String name) {
+    protected void check(String name) {
         if (name.indexOf("rulesets") == -1 && nameMap.containsKey(name)) {
             append(nameMap.get(name));
         } else {
@@ -33,7 +33,7 @@ public class SimpleRuleSetNameMapper {
         }
     }
 
-    private void append(String name) {
+    protected void append(String name) {
         if (rulesets.length() > 0) {
             rulesets.append(',');
         }
diff --git a/pmd/src/net/sourceforge/pmd/ant/PMDTask.java b/pmd/src/net/sourceforge/pmd/ant/PMDTask.java
index 2cdc748a16..63dd5c68e7 100644
--- a/pmd/src/net/sourceforge/pmd/ant/PMDTask.java
+++ b/pmd/src/net/sourceforge/pmd/ant/PMDTask.java
@@ -157,8 +157,24 @@ public class PMDTask extends Task {
         createLongAuxClasspath().setRefid(r);
     }
 
+    private class AntTaskNameMapper extends SimpleRuleSetNameMapper {
+        public AntTaskNameMapper(String s) {
+            super(s);
+        }
+
+        protected void check(String name) {
+            if (name.indexOf("rulesets") == -1 && nameMap.containsKey(name)) {
+                append(nameMap.get(name));
+            } else {
+                // substitute env variables/properties
+                append(getProject().replaceProperties(name));
+            }
+        }
+
+    }
+
     private void doTask(){
-        ruleSetFiles = new SimpleRuleSetNameMapper(ruleSetFiles).getRuleSets();
+        ruleSetFiles = new AntTaskNameMapper(ruleSetFiles).getRuleSets();
 
         ClassLoader cl;
         if (classpath == null) {
@@ -168,13 +184,22 @@ public class PMDTask extends Task {
             log("Using the AntClassLoader", Project.MSG_VERBOSE);
             cl = new AntClassLoader(getProject(), classpath);
         }
+        /*
+         * 'basedir' is added to the path to make sure that relative paths
+         * such as "<ruleset>resources/custom_ruleset.xml</ruleset>" still
+         * work when ant is invoked from a different directory using "-f"
+         */
+        String extraPath = getProject().getBaseDir().toString();
+
         if (auxClasspath != null) {
             log("Using auxclasspath: " + auxClasspath, Project.MSG_VERBOSE);
-            try {
-                cl = new ClasspathClassLoader(auxClasspath.toString(), cl);
-            } catch (IOException ioe) {
-                throw new BuildException(ioe.getMessage());
-            }
+            extraPath = auxClasspath.toString() + File.pathSeparator + extraPath;
+        }
+
+        try {
+            cl = new ClasspathClassLoader(extraPath, cl);
+        } catch (IOException ioe) {
+            throw new BuildException(ioe.getMessage());
         }
 
         final ClassLoader classLoader = cl;
@@ -340,18 +365,6 @@ public class PMDTask extends Task {
             ruleSetFiles = getNestedRuleSetFiles();
         }
 
-        // convert relative paths and substitute env variables/properties
-        final StringBuffer sb = new StringBuffer();
-        for(String s: ruleSetFiles.split(",")) {
-            Path p = new Path(getProject());
-            p.setPath(getProject().replaceProperties(s));
-            if (sb.length() > 0) {
-                sb.append(',');
-            }
-            sb.append(p);
-        }
-        ruleSetFiles = sb.toString();
-
         if (!targetJDK.equals("1.3") && !targetJDK.equals("1.4") && !targetJDK.equals("1.5") && !targetJDK.equals("1.6") && !targetJDK.equals("1.7") && !targetJDK.equals("jsp")) {
             throw new BuildException("The targetjdk attribute, if used, must be set to either '1.3', '1.4', '1.5', '1.6', '1.7' or 'jsp'");
         }