Hi Phil,
I used a virtual midi router for this task. SoFo has one, but I tried the midi yoke 1.71, in Win XP. In SONAR I selected the midi in (midi yoke 1), and in Vegas midi out, the same midi yoke 1. All you have to do next is to "tell" Sonar to chase the midi time code, and Vegas to generate MTC. that's all
Good luck