Multi Module project problems

Hi, I'm having some issues with setting up a multi-module project in 4.0.3, so wanted to see if anyone's got any comments.

I've got a J2EE app that I currently build with Xdoclet & Ant - It's targeted to but not specific to WL so I thought I'd try & use it as an test of the module support.

It's currently a set of sources under src/java, where I use Xdoclet to generate the support files to src/generated_java. I then build a number of java jars, bean jars, wars & an ear, selecting the particular packages in each from the common classes tree.

My first try was to simply create the various modules, each of which would have the src/java tree as it's source route, but with the folders used by the other modules marked as excluded. The problem with this was that when all the modules were done, IDEA showed all the files as excluded, i.e. appearing to take the exclusions as cumulative irrespective of active module...

My second try was to create seperate src/java trees, e.g. src/java_Common, src/java_AdminWAR, etc. I've not split the modules further, but this has given me odd results, in that one of the modules will appear to have sources, whereas the other ones won't. It occurs to me that they've all got the same content root and this is a problem, despite differing src trees...

It's seeming to me that they only way the multi-module support works is with different content roots per module. Is this correct?
If so, it's a shame, as it's going to be a pain changing existing structures & build scripts if I want to use the J2EE support, or has anyone been able to get this working from a single source tree? If so, any tips? :)