I have a contact named Conference. The number (in your format) would be:
1-800-555-2121p111111

Note two things: 1. You put it in as "Conference" not in the notes/appointment/calendar.
2. I used P not W so you have to hit the Talk/Send button to send the password

I know this isn't a solution to your problem, and I'm not a developer that's going to solve it... I am just suggesting a temporary workaround until someone does

Ehud