Check your MOSS sheet to be sure you have the Centralized VM feature. Naturally your routing tables need to be pointing exts from one box to the other. Feature Access codes for MWI set/clear need to be the same on both machines. Also, if you're attempting to use a NodeID on your 200ICPs, beware that feature is broken in all presently shipping software. I understand there is an open DPAR on it.
The 200ICP supports a mutation of CCS trace that has to be enabled through telnet port 2002, tho I dunno if you can see the MWI traffic there or not and I don't have the enable command handy (it's much different than the CCS Trace command set on the 3300 and SX2K)