I'd used this briefly with Orbiter 2010, I remember some troubles but I did get it to work.
Looking at the config file.
[ANIM_SEQ_6]
; Cargo Bay Doors / Docking Tube & Airlock Deploy
KEY=0
DURATION=6
It's defined as a zero. So I don't see why it wouldn't work. Toggling the numpad on/off for SC3 craft gets annoying sometimes. I'll load this up and see what shakes loose.
I'd meant to run the BSP through Artlav's sc3 to dll converter to see how it turned out but I never got around to it. It worked A-OK for the executive spaceplane...
EDIT - - -
Alright, I just did a quick flight to LEO; after remembering to use ReleaseMFD to separate the BSP from the carrier I did get it to open the cargo doors. toggling [NumLock] and using [Left Shift]+[Numpad 0] opened them up. I think [Left Shift]+[Numpad 9] extended a docking collar out into the cargo bay.
I did get some strange graphic artifact when I toggled the numpad on and off. a little box in the lower center of the screen. It went away quickly, I think it's a graphics card thing.
Sorry I can't reproduce your issue, but it works for me. :shrug: Are you using a laptop by any chance? Sometimes those keys work oddly. There is a workaround I think by rebinding the keys.