Some useful information there about the Steam IDs, though I’m not sure how much of that I can use because unfortunately Variator doesn’t use Unreal’s networking, it uses direct UDP connections.
The Steam equivalent of that would be SteamNetworkingMessages, which the UDK Steamworks subsystem doesn’t seem to support.
Getting UDP to work was already a huge ordeal. I had to write my own DLL to handle it, and UDK’s DLL binding has serious problems when you’re using the 64-bit version (it needs crazy workarounds because it can’t pass 64-bit pointers properly.)
I did try to see if I could get my DLL to load the Steamworks DLL, but UDK just refused to call any bindings on the DLL when I tried that. I don’t know if it would maybe have worked if I got the headers for the ancient version of Steamworks that UDK uses, or if the idea of UDK loading a DLL that calls another DLL is just a non-starter altogether.