I was able to set up WSJT-X to talk to my G90 without using FLRig. See the setup instructions in the post link below: New cat program - #10 by KQ4SFG
I am assuming that the DIGIRig is agnostic about what CAT control program it works with, but I could be wrong. If I am I then you should be able to work around it by adding Gridtracker to your setup and using it’s pass-through capability to forward the UDP feed from WSJT-X to WRL CAT. See below: Gridtracker/WRL Cat passthrough [HOW TO]
Let us know how it goes!
KQ4SFG, 73