I've tried several times to get youmail setup on my storm, but to no avail.
I sign up, sign in using my activation code, I go to the blackberry devices and pick a phone, enter the number that is supposed to forward your voicemail to youmail instead, hit the send key then the disconnect key once it connected.
I then test it out and for whatever reason, it just does not work. For some reason I don't think the voicemail is being forwarded like it's supposed to.
I tried to enter the new forward number in my bb myself, but it would not save the new number, I called t-mobile bb support, they changed it for me, even set it up so that if I hit the reject button the caller(usually spam) gets sent to youmail and hears a very nast message and can not leave a voicemail. When the bb is off the caller goes to my t-mo voicemail, and if I just don't answer the call it goes to my t-mo voicemail. I also use white & blacklist to reject certain callers for me. Works great.