I don't know if you are a member at PT.com, but there is a thread which is monitored by a Holley support person (Derek) who may be able to help...
http://www.pro-touring.com/showthrea...-Inside-Please
I don't have a Dominator setup myself, but I do have an HP EFI. Based on my reading of the manual, I don't think there's a way to do this. The Holley setups do drive CAN bus outputs, and recently Speedhut announced gauges that take CAN inputs. But I have no idea if the two have been tested together...
I am about to start wiring up my gauges myself. I'm going to wire them to a second of sensors on the engine. I will drive the tach from the HP EFI (it can do that), but everything else will come from dedicated sensors.
Good luck!