Here’s a reply direct from Sony on the Vegas forum:
For both Decklink and Aja, ONLY SDI capture and print to tape is supported. Analog capture or print to tape is not supported and quite likely willl not work at all (or if it does there may be serious problems).
Component video monitoring from either card IS supported.
We understand that there are still a lot of BetaSP decks out in the field and reccomend the Convergent boxes for capture and print to tape for SP and other analog decks.