This is not something that can be done out of the box within the configuration screens, though this can be done.
Although the following documentation comes from the TG585 v7 information, it is still valid and the commands are pretty much the same as the ones used have not changed. Do note that the interface names will be different, along with things like the PVC numbers (they use examples of 8.35 were we use 0.38). There is also the fact this is completely different again for fibre usage.
http://www.technicolorbroadbandpartner.com/getfile.php?id=5882The main scenario from the document you want is Transparent NAT. This means NAT works as standard, but certain IPs routed are transparently passed through without translation.
Others includes Multi-NAT.
Read the Introduction to each NAT scenario, which should help you understand what that scenario would deliver, and pick one according to your needs.
Do note, we are unable to provide support for using these functions though. The core software provides these, but it is using the router beyond the scope of standard NAT-only or No-NAT.
