Maven2 ressource processing - editing xml file

[Weichselbaumer Michael (MWE 4170)]

Hello!
 
I need to edit some configuration files which are in xml-format during
building with maven.
Some values, that change from build to build (e.g. buildnumber) need to
be written to the xml-file (value for attribute) - is there any plugin
capable of doing so or how does maven accomplish this?
 
If there is no plugin, which buildstep should I use to achieve this?
processressources?!
 
Thanks for your help!