Send 'Contract Approval' Completion/RFI notifications to someone other than the contract creator

Requirement:
Send 'Contract Approval' 'Completion'/'Request Info' notifications to someone other than the contract creator.

Solution Attempted:
1) Created a Global DFF to store the username at contract header.
2) Synchronized DFFs to BPM.
3) Updated the BPM task mapping to refer to the new DFF for Complete/RFI notifications.

Issue:
Despite following the above steps, the BPM completion (FYI) notification is still sent to the contract creator. The default user for the Request Info task still appears as the creator.