Ok, I was on the phone with an actual TT agent for 2 hours and we successfully got the return submitted. On the form 592-B, if your withholding agent has a FEIN, you put that FEIN number in the box below where it says SOS number. You leave the box that says SSN/ITIN number blank. I think I included the dash in the FEIN number in the box. Hope this works for you!
