Bumpity bump. Any info or advice is muchos appreciated!
I use an AJA Xena capture card with a Sony BetaCam 2800 recorder with no issues.
But, I have to run the 9-pin into the Xena's serial port, not the PC's. And, you have to select that port in the capture window's settings.
For more detailed help, I suggest you post on Creative Cow. There you'll find more higher-end users that have these third-party add-ons. I find that the forums here are mostly filled with out-of-the-box "casual" editors/users.
The Addenda Electronics adapter model RS-4/U performs an electrical *and* protocol translation such that your UVW-1200 or -1400 can be used in place of a regular studio deck that supports RS422. The -4/U actually reports itself as a UVW-1800 deck in order to keep the editing software happy. See more at www.addenda.com.