Actually, there are really 2 problems,
- this one - which I think should be reopened.
- And, I think there is also a problem with the way the 'src/main/resources' directory is handled.
The on-line doc for the plugin says that 'src/main/resources' files will be copied to the target/classes and WEB-INF/classes but they are not, they are instaed copied to the WEB-INF directory. You can try to work around this by specifying the targetPath ... but, of course, that fails due to the underlying problem with targetPath (MWAR-54). Do you want me to open up another problem, i.e., that src/main/resource files are not copied where the doc says they are? This 'bug' could be 'fixed' by changing the doc 
WRT MWAR-54:
The changes that marvin made to 'fix' the problem were definitely required - but they were not sufficient to correct the problem, at least when doing a clean build on a windows xp system.
(note - there are additional fixes that should be made to the logging messages to accurately reflect what is going on - but i don't think there is anything incorrect about the code in the plugin inself)
I think the underlying problem is the behavior of the copyFileIfModified method.
I have not had the time to setup my machine to build maven (I was able to easily build a modified version of the plugin ... maven happily loaded up my machine will all the necessary pieces) - so I have not looked at this code.
with test case