No TX power in Dig Mode on TX-500

Since I can’t find any other posts about this problem I must be the only one. From Digirig Mobile v1.7 I have a CAT cable that is working perfectly and a REM/DATA cable from the audio port. Testing with FLDIGI/FLRIG as this has a very nice rig driver file that accurately implements the limited Kenwood TS-2000 protocol commands this radio supports. I can see received audio on the FLDIGI waterfall, I can see TX audio level on the radio’s band display. But output power meter remains at zero. Tried both DIG and USB mode while using PSK-31 codec. I use this same antenna for other radios so I know it is resonant and doesn’t need a tuner. I have a faint memory of getting the TX-500 to actually transmit digital modes but only by moving the TX audio over to the MIC/SP audio input. I’ve tried to vary the Menu 09 Mic and Dig Gain. What am I missing?

There is step-by-step tutorial for TX-500 setup with Digirig from their mailing list. You can find it in this discussion: | TX-500 and DigiRig Interface / Cables - Any Guides?