You shouldn't need anything to control you amp, it's just an amp, it doesn't adjust the sound volume, the volume control is via the 8x8 or 16x16 switcher / pre-amp. The only thing you can do with the phast software to the amp is set the maximum volume level - ranges from 0 to 99, but you can do that manually. There's 2 buttons on the back of the amp that let you raise and lower the level of each of the 8 channels.
I'm using 5 of these phast amps with my HTD MC-66's to run 20 zones in my house. Great sound and you can find them from about $120 on ebay.