Implementing the security for FSCM

Hi ,

We are going to implement FSCM module as currently R/3 4.7ee 200 exists in our landscape and for this FSCM implementation they have planned to Install Standalone Java stack system for Accessing Biller direct (netweaver2004s) and ECC6.0 with only abap stack for accessing Dispute management .

what i am concern from Security perspective that what are the requirements we need to check and inputs required from functional and Business teams.

Do we have to create the user ids in all the three systems and role mapping between Java system and ECC6.0/4.7ee systems?

Regards,

Dheeraj