I have had a 7100T and I now have a 8700G. I have never been able to figure out how to use the function to allow me to leave a voicemail for someone on my company voicemail. What I mean by that is that everyone has a 4 digit code (lets say 7879), but if you do not know their code by hard, you can start to spell their last name by pressing the appropriate alphanumeric keypad on any ordinary (cellular phone or land-line) to leave them a message. Well, that does not work with the BBs and it is VERY frustrating when you are trying to leave someone a message. I have asked several people at my company and no one knows how to do it with the BBs. Are we all idiots or is this just not possible? Yeah, maybe we are all idiots, but I would like your help nonetheless. Then I can help everyone with this problem because people are printing off list with everyone's extension and carrying it around with them, which is really inconvenient. Any help would be greatly appreciated.
when you need to use the number keys to spell the name you need to press the alt key then the apropret number you just need to remeber that 2 is abc 3 is def 4 is ghi 5 is jkl 6 is mno 7 is pqrs 8 tuv 9 is wxyz
Have you tried pressing Alt + the letter you're trying to type (you need to hit alt for each letter or activate the alt lock)? This is exactly how you dial by letter on the Blackberry.
When I hold down ALT and press S-M-I on my keypad, my "dial-by-name" on our voicmaill system takes me to the SMITHs, for example. This also works when dialing phone numbers, like +1212RAMDOM1.
And don't forget that you can add two second pauses using comma (N) or a wait prompt using exclamation point (B).
I say comma and exclamation point because that's what they show up as in Outlook, although I'm not certain using those characters in Outlook will work - just never tried.
Using 8700 with company voicemail
this might work
) while dialing numbers. 
