I'm running a 706 with an ATAS and am extremely pleased with the setup. Perhaps not as efficient as a High Sierra or other better Q antenna, but I've worked my share of mobile HF with it. Pictures are on my website.
Yes, Amcomm does sell a control box for about $75 but all it is is an 8V regulator, a switch, a coil and a capacitor. $10 at any Radio Shack. When you put 8V on the center pin of the antenna coax the antenna goes one way, when you put 12V it goes the other. Controlling the antenna through the coax is nice because you don't have to route a separate wire to the antenna. Aside from not being seamless operation with the 706 they do work well together.