SmartSDR CAT "Slice not Present" question

I am beta testing one of the major commercial Rig Control / logging programs in order to add FlexRadio support. This SW must interface via serial so I must use SmartSDR CAT to create the serial COM link.

When operating on a local LAN and SmartSDR everything works fine with SmartSDR CAT displaying "Auto Switch TX" in blue. The 3rd party Rig Control program works properly. But when I switch to my remote site, SmartSDR CAT displays "Slice not present" even though the correct slice is actually displayed on the PC.

I have identical 6500's at both locations and both locations are working normally both with the PC access and via Maestro ... except for CAT. I am using Beta_1.10.15 but I see the same issue on previous CAT versions. The only obvious difference is the average ~55mS RTT ping times when connecting via the remote site.

If SmartSDR CAT is using UDP packets, that might be the issue as they will not be forwarded remotely in my system. I have not had a chance to look at the NW traffic while doing this. My network linking isn't a typical VPN connection.  

So my questions are:

Does SmartSDR CAT use UDP to connect the slice?

Is anyone remotely using a Rig Control program via SmartSDR CAT and VPN successfully?

Any known issues with longer RTT ping times or suggestions?

Fred
K9SO