Generation Viewpoint & Xtend

Hello !
I am trying to use xtend-lang to transform the capella model.
I have a problem when I use the viewpoint generation tool.
The xtend-gen folder seems not to be considered as source during the viewpoint generation.
I implemented a popup menu ui in a java file which command an handle using the generated code by x-tend.
This ui does not work as soon as I import the package in which the xtend-gen file, and in particular the xtend libs, are contained…
Do you have an idea why this is not working ?
Thanks

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