I figured I'd not something on here since I couldn't find any concrete info on making this work.
So, there appears to be a bug in the Sonicwall OS as it related to the native "SIP Transformations" functionality that is supposed to translate public IP's from Private IP's on SDP's between a NAT'd CUBE and a Public IP ITSP. The issue is actually a bug in the Sonicwall OS.
What is happening, is the Sonicwall only transforms the first Connection (c) attribute of the SDP, and CUBE sends two or more per RFC allowing for that. We're working with them to fix that, but until they do, I think the only way to get this to reliably work is to turn off Sonicwall's SIP Transformations feature, and do your own SDP rewriting on the CUBE itself. It's not as elegant, but that will work.
There's no dedicated setting for that, just the one checkbox for enabling SIP Transformations. Sonicwall has admitted this is bug in non-compliance with the SIP RFC for having multiple connection (c) lines in the SDP, which the CUBE sends out. We're waiting to test a hotfix they provided, so hopefully that'll resolve our issues and end up in a SonicOS build later on.
These are the paths to get to each CCX logs through CLI. They may be helpful if you are having issues accessing RTMT or downloading logs through it.
If you want to download them you have to prefix "file get " and you can add one of the options (re...