Based on the following discussion on sme-bpm mailing list, document that a correkationKey does not get carried on to the sub processes:

Ian Watson: When using correlation key are there any steps required to pass this onto sub processes?
Ie If I invoke a process on kie-server using

/instances/correlation/

Is the correlationKey automatically passed onto all sub processes invoked? Is there a special attribute in the assignments to use?

Maciej Swiderski: at the moment (6.x) correlation key is not propagated down to subprocesses. It was added to master (v7) as part of on going work on case management. The mechanism is that the correlation key is added in following format:

• parent correlation key
• process id of the subprocess
• timestamp
  this is done to make sure correlation keys are unique for active process instances while still easy to search like correlation key (of the parent) in like style to get all correlated process instances.