Enhance User authentication in REST API for performing task operation in BPMS 6

Issue

Some operations in the remote java API and the Rest API has different signatures.
For example:

Java API: taskService.release(Long taskId, String userId)
Rest API: /task/{taskID}/release

The java API has a user to make remote connections, and this user may be different to user that we uses in release task operation. The Rest API only have the request Authorization header for user, and we supposed to the API uses this user and permissions to release tasks.

• How to use different user for REST API authentication and for task operation ?