Hi again,
I've created the sample project. There are nothing wrong with the JMS p2 or the 3.7.1 p2 being provided by ECF team ! Sorry for the time lost, guys !
We discovered the problem... it was a trick from maven/tycho and a long headache for me :(
For this project we separate aggregators pom from parent pom, so not every project/module inherits from the same parent inside one agreggator. That bring us some facilities but it could be dangerous.... :)
And was that what happen: our p2 project (that is consuming our ECF headless feature) was using a different parent pom than our ECF headless feature project.
Instead of I do set the JMS p2 repository in the common parent of both parents, I set it in our ECF headless feature's parent only.
So, when tycho was building our ECF headless feature that consumes ECF JMS feature, everything was ok. But when it tried to build the p2 project then tycho failed because the repo wasn't there... :-/
I would like to thanks everyone here that tried to help me. your suggestions help me to figure out !