I need to setup a new VC system and right now I have so many options and mixes that I find hard to decided on.

we already have CCM5.1 and I am sourcing for a new VC system and I hope the new VC system is able to leverage on our existing CCM5.1 Infrastructure.

The system should also be able to use both IP and ISDN gateway for the IPtel to connect to multi sites

On hand I already have a polycom VSX7000 solution that seems viable, however is this easily integrable into the IPTEL environment and make VC using our VGW? Do I have to invest into polycom MCU to enable the system to connect to other VC via another set of BRI lines?

Also I am interested to find out if CVTA can make offnet video calls through the PSTN?