Accessing R3 with TREX user index_service

Hi,

Does anyone have an idea or suggestion regarding the usage of the Portal user "index_service" to access R3.

"Index_service" is too long for R3 (max of 12 characters). We need to access R3 to index info using TREX. Unfortunately, I keep getting "Der Aussteller des SSO-Tickets ist nicht authorisiert" errors, which means an SSO error. The user "index_servic" exists in R3 and with a user mapping for the TREX user "index_service" to Portal user "index_servic", I can open a SAP transaction with the SAPApplication Launcher.

Is the creation of an ACL for TREX and its input into the R3 necessary? Or does TREX just use the Portal ACL when it accesses R3 using the various Repisitory managers.

Thanks,

Dick