yes, I have connected a sx-200 bay, to a 3300MXE, rls9.0. worked fine. does not support trunk cards (ie LS/GS) in the per cabinet. I used embedded CIM port to connect to CIM module on Bay Contoller III card.
You will find the sx-200 bay programming, under heading for ASU, not PER cabinets. Once you identify the bay # to the system here, then go into Per Cabinets, card assignmemt, and program up your cards. be careful to choose the correct cards (ie, not just ON? or Dnic, you must choose the ones specifi to a 200 cabinet, such as ons 12port, dnic 12 port, or something like that. -** if you have the cards installed, they will sow installed, and will give you the proper "name", so it's easy to match up programmed type to installed type.