Not Enough Audio from Computer (&HRD) via DAX to Get Enough RF Output

Using SmartSDR 1.4.11, Win7 Pro Service Pack 1, HRD 6.2:

When transmitting digital signals from DM780 I get virtually no RF power output on the 6500 with the DAX control panel and the SmartSDR level set to 50%.  I see about -30dB on the level meter.

When I crank the DAX TX control and the SmartSDR control up to 100% I can get about 80 watts of RF out.  I don't like setting anything at 100%.

In Win7 Pro the sliders are set at 100%.

I can't find anything in DM780 that allows me to up the audio output. In the "Soundcard" flyout on the left side of the screen there is a transmit level slider but it does not work.

Is anyone aware of a buried control in DM780 that will allow me to up the audio output?

Thanks much! 73 Frank N1UW