[Serusers] SER, IPv6, IPv6/IPv4 interworking and more

Hello After installing and running over last month SER, we are going to the next step. Our final goal is to deploy a SIP network which allows SIP clients Voice Call, Videoconference (RTP), Instant Message and Presence. And we want to use IPv6 and IPv4 networks. I wonder several questions about this: I'll use a SER server for IPv4 network and another for IPv6 network, but how I connect them? I think that I need a device with two network cards connected each one to IPv4 or IPv6. Which software has to run this device to act as a SIP Protocol Gateway? Can SER do this? Do you think that with the two proxy SER servers and the SIP Protocol Gateway would be enough or that I need another device to develope this? Thank you very much for your time and responses Curro