I did it on a DSX40 not too long ago. No there isn't any white paper for TW, but NTAC assured me it would work and yes it does. The set up was unusual in that the DSX does not go through the local LAN but through a direct connection that TW provides. Because of that, they will need to provide you with an IP address for the DSX as well as an address to point to. Also make sure you have the absolute latest software available before proceeding. In the DSX there was a flaw that blocked international calls. The upgrade fixed it.
One last note, the customer I installed this for is dropping TW because of outages and technical issues.
Put on your crash helmet, you may need it.

St Petersburg