Unable to create xhtml file

When creating a file with extension ".xhtml" with the following code the returned XMLResource is null. However creating the same file with extension "xml" works.

XMLResource config = resourceFactory.create(XMLResource.class, new File(project.toString() + "/src/main/resources/" + filename));

imho the create() method should produce an exception containing the cause of the error instead of returning null, it would simplify bugfixing.

Furthermore the code getParent().mkdirs(); (2 occurences) in org.jboss.forge.addon.resource.AbstractFileResource may (and do) produce NullPointerExceptions.

Is there any suggestion to get the base resource directory via code instead of hardcoding it to "project.toString() + "/src/main/resources"?

thanks and regards from austria, Mike