If you're using Sametime 8.5.2 IFR1 and TCSPI ver 2.0 to talk directly to the RMX, then we're no longer testing direct integration with RMX versions. It should work, but it's strongly recommend you move to the go-forward architecture which is:
Sametime 8.5.2 IFR1 to TCSPI ver 3.0 to DMA (and then to RMX).
When you move to Sametime 9.0.x, Polycom supports Sametime 9 to TCSPI ver 3.2 to DMA (to RMX).
All new RMXes builds are currently only being tested with Sametime 9+