Eclipse WTP and Maven project producing two artifacts

I have a maven jar project common_platform that is producing the usual .jar file and also a .war overlay (using the maven-assembly-plugin)

I have another maven project with war packaging, it's including both those artifacts.

Now I want to use WTP to deploy the webapp project to Tomcat. Unfortunately the common_platform .war overlay is not getting processed.

If I go to Web Deployment Assembly view I see the project is included twice, but the files do not appear in the deployed webapplication.

I have another (external) overlay with ExtJs and it's being unpacked as expected. I tried adding the package manually to the descriptor, but it's added as a package, not unpacked.

How to make WTP unpack the overlay contents?

I'm using Eclipse Mars with recent WTP, m2e and m2e-wtp.

Filled a bug in m2e-wtp

TL;DR:

Unfortunately m2e-wtp doesn't support workspace projects generating multiple archives.