Thanks Maciej for helping.
I try what you told me but with no success.
Here are my steps :
1- Make a first REST API Call
2- Make an authenticate call => OK
3- Make a HTTP Post call using a MultipartEntity with a single parameter => only one process variable in my process, REST API function used : http://localhost:8080/gwt-console-server/rs/form/process/process_id/complete
Whenever I execute that sequence I get a HTTP 401 error code dealing with authentifcation problems at step 3 although I authenticate successfully at step 2. Can you give me some further help so that I can accomplish the 3 steps mentionned.
Actually at step 3 it is as if my authentification had been lost...
Regards