I have received a reply from Vidac regarding my NTSC question, this is what they wrote:

Hello,

the TV tuner doesn't support NTSC, it is a PAL B/G tuner.
The compression engine supports NTSC because it's no difference between PAL and NTSC from the IC's point of view
So you can use transcoding with NTSC to NTSC and PAL to PAL, format conversion is possible with DirectShow but it drops frame only, no high sophisticated algorithm and we couldn't recommend it.
For direct capture NTSC isn't supported, because the videofrontend BT829 needs another quartz for that job.

Due to this reasons, we sell the card only to "PAL countries".


Best regards and a happy new year

VIDAC support

I also asked if Vidac were planning to build a NTSC card, they replied: "yes, we would like to offer a NTSC only card.".