Whoa there, there IS a way to make SONAR work with HUI, but it is only in a limited way. I use SONAR with HUI every day (well I do use it every day one more now my brief but torrid affair with Cubase ended in bitter acrimony). The controller you want is called C.M. Labs MotorMix. Really it's only faders that work, but they seem very solid and faders are really all I need. Probably doesn't really make the most of that shiny new mixer though.
Why on earth Sonar doesn't properly support one of the most common protocols is beyond me. But there again a lot of thinking behind Sonar is beyond me....