Problem with dependency conflict resolution on multi-module project

Hi,

I'm trying to use the assembly plugin to gather all the jars of my project, including all dependencies.
As the project is composed of several modules, I use a descriptor which looks like this :

<assembly>
<id>bin</id>
<formats>
<format>zip</format>
</formats>
<includeBaseDirectory>false</includeBaseDirectory>
<moduleSets>
<moduleSet>
<binaries>
<outputDirectory>/</outputDirectory>
<unpack>false</unpack>
<includeDependencies>true</includeDependencies>
</binaries>
</moduleSet>
</moduleSets>
</assembly>

It seems to work fine at first sight - it creates a zip containing all the jar files. However, I find in the archive several instances of the same dependency with differents versions, for instance asm-1.5.3 and asm-2.2.3. This is a surprise as maven is supposed to take care of conflict resolution.

When I look at a detailed trace, it appears that conflict resolution is done but on each module independently. But my modules are intended to work together and I expect to get an assembly with only one version of each dependency found on the whole set of mudules. It seems to me that conflict resolution is not managed properly in this use case.