IntelliJ 14 and Maven jar plugin

Hi there. I have a problem with IntelliJ 14 and the Maven jar plugin. We use this to build add-ons for a standard software. In these add-ons we are also able to override classes, that are defined in the standard software. Nevertheless, this usage works fine with NetBeans, but I'm not able to make it work with IntelliJ. The overriden classes seem not to be noticed by IntelliJ, when I use the Go to -> Declaration functionality. Is there a tutorial to use IntelliJ and Maven in that way? Help is very apprectiated. Thanks in advance.