If you want to use BSB to generate an OPB-based system, you should start with EDK 9.1i as Bill indicated.
if you simply want to be able to access the legacy OPB and PLB v3.4 cores (they are still there in EDK 9.2i), you should do the following:
XPS, Edit -> Preferences, IP Catalog and IP Config Dialog, enable the Display "Available" IP cores (including legacy PLB/OPB cores) in IP Catalog.
Cheers,
bt