You can map controls on a midi device to change just about anything you can change within the Pianoteq application. I've been working on an iPhone/iPad app solution over the last couple days that lets you build up an interface to do this. It will let you change just about anything you'd want, you just need to take a little time and set it up.
One of the issues is how it will connect to your PC. I'm connecting an iPad to a Raspberry Pi PC over wifi using rtmidi protocol. Bluetooth midi is another option. Or just connect your midi device with a usb cable, easist way to do it technically but a little less flexible.
I hope to post about my solution in the next day or two.