Did you ever figure this out? I just got a Hauppauge HDPVR Gaming Edition and was hoping to upscale my VHS deck. I haven't had any luck yet.
The composite to hdmi converter I got from Monoprice was useless. It introduced a horrible green wash to the video when it was connected to the HDPVR but not directly to the tv.
I know it can be a bit of a waste to upscale VHS but for future generations of alien historians, I want to start with a large enough recording.