Well, we now have call pickup and steal, and busy lamp fields, and ring groups...
So time to test - the support number will be directed via the new system.
First sign of trouble and we'll switch it back to the old system... But it is a Friday afternoon, so lets give it a try :-)
Follow-up: I have registered my mobile via the new system back-to-back in to the main call server, which means I can have a busy lamp light on my desk phone for my phone, and steal calls both ways - that is cool!
This is a real winner for the SIM2SIP stuff we do - very cool indeed.