When you’re trying to integrate external webservices into your bpel process and you need proxy authentication you will probably run into the following bug: 5851338.
A patchset is made available to resolve the HTTP-407 issue in your BPEL Environment. For more detailed information :
1) Download and review the readme for Patch.6869621 ( MLR # 7 of 10.1.3.3.1 )
2) Apply Patch.6869621 in a test environment.