Here is the problem, I use the maven nbm plugin to create a webstartable app (nbm:webstart-app) on CentOS 6.
If I am using java 1.7.0 update 2 - there is no WEB-INF/lib/ folder in the generated war file, subsequently, the $$codebase values are not modified by tomcat (version 6 in this case) and the application cannot be used.
BUT, if I use java 1.7.0 update 1 - the WEB-INF folder is created in the resulting war file and everything works file and the $$codebase problem is gone.
Have you run Maven with the -X option in each case and compared the output? That might give you some clue as to what is going wrong in the plugin. Other than that, you might have to debug the plugin to find out what the difference is.
(We ran into similar issues using 1.6.0_28, and thus went back to 1.6.0_26)
Bit too late, but i had the same problem. i don't know why, but after downloading JDK "Demos and Samples" (they comes in seperate download) and placing in %java_home% directory maven nbm plugin begin generate war with WEB-INF/lib/ directory and jnlp-servlet.jar.
it is enough to copy only "sample\jnlp\servlet" with content to %java_home% directory.