I need to distribute an Access mde as a "trusted" application. So I got a certificate, but I can't figure out how to use it!

I have:
  • a *.p7b file, which I installed (I think)
  • a *.pvk file - I have no idea what to do with this, and
  • a password.

When I installed the p7b, I put it in the "trusted publisher" store, but I was just guessing. When I try to sign the code, the certificate isn't on the list.

Can anyone give me some guidance?