So, I've fixed this adding a new "Specified paths are relative to HUDSON_HOME" checkbox to the build wrapper. This works fine.
I still need to see how I can tweak the checkUrl associated to the includes and excludes fields so that it dynamically takes into account the state of the checkbox for the validation. For the moment it is:
'/job/xx/'+'descriptorByName/com.michelin.cio.hudson.plugins.copytoslave.CopyToSlaveBuildWrapper/checkIncludes'+qs(this).addThis().toString()
Also, the "workspace" folder is automatically created when required.
I think I can solve this by doing the following:
Your thoughts on this?