If you use Kalle's example for the payloadXML you should still be able to call bria the way you were doing it before
Launch.RawParam: {Path} C:\Program Files (x86)\CounterPath\CounterPath Bria Professional\BriaProfessional.exe {Parameters} dial="{1}"
this will be more reliable than using dxinput. I assume that bria will work with this parameter whether it is already running or not, but anyway, you probably have it running all the time.
I think this tutorial will be very helpful for you to watch so that you can understand a bit better how to work with payloads:
part A
part B
&feature=relmfu
thanks Kalle for "manning the phones" while I was away (as usual)