How to obtain the primaryFile:path variable before the CHECKIN_UNIVERSAL service is called.

I am trying to get the file using JAVA to update and do the check-in.  In 11g, I could get the filepath to the vault directory using the binder variable 'primaryFile:path

(/opt4/bea/user_projects/domains/ecm/ucm/cs/vault/~temp/203322445.docx)' before the CHECKIN_UNIVERSAL service is called. However, in 12c, the same code is not working and the variable 'primaryFile:path' is not available in the binder. 

Any idea how to obtain this variable before the CHECKIN_NEW service. Any help is highly appreciated as we are closing on the deadlines for this project.