DefaultAddResource cache disabled because of the Maven build

Since the build is done by Maven, the ant code that was parsing the commons/src/main/resources/org/apache/myfaces/renderkit/html/util/AddResource.properties
by replacing the @lastModified@ tag with the build date is gone.
So the file in the jar now contains
lastModified=@lastModified@
instead of something like :
lastModified=2006-02-14 23:47:48 +0400

The effect of this is that the resource files aren't cached anymore.

I'm still very new to maven, so I don't know yet how to restore this in the maven build.