Index: src/main/java/info/magnolia/module/form/processors/BaseFormProcessorImpl.java
===================================================================
--- src/main/java/info/magnolia/module/form/processors/BaseFormProcessorImpl.java	(revision 28021)
+++ src/main/java/info/magnolia/module/form/processors/BaseFormProcessorImpl.java	(working copy)
@@ -58,6 +58,7 @@
     private String name;
 
     private boolean enabled;
+    private String multiValueSeparator = "__";
 
 
     public String process(FormProcessor processors[], FormModel model) throws Exception {
@@ -100,8 +101,7 @@
         while (i.hasNext()) {
             Entry pairs = (Entry) i.next();
             String key = (String) pairs.getKey();
-            result.put(key, StringUtils.join(MgnlContext
-                    .getParameterValues(key), "__"));
+            result.put(key, StringUtils.join(MgnlContext.getParameterValues(key), multiValueSeparator));
 
         }
         return result;
@@ -123,5 +123,24 @@
         this.enabled = enabled;
     }
 
+    /**
+     * @return the multiValueSeparator
+     */
+    public String getMultiValueSeparator() {
+        return multiValueSeparator;
+    }
+
+    /**
+     * The separator provided will be used to separate multiple form parameter
+     * values. So for instance if you have multiple "interests" checkboxes in
+     * a form and the usere checks "Skiing", "Surfing" and "Soccer" and you 
+     * configured the form processor with ", " as separator, you'll end up with
+     * "Skiing, Surfing, Soccer" as value.
+     * @param multiValueSeparator the multiValueSeparator to set
+     */
+    public void setMultiValueSeparator(String multiValueSeparator) {
+        this.multiValueSeparator = multiValueSeparator;
+    }
+
 }