I just switched back to blackberry and bought a new 8900 but something weird seems to be happening when I compose an email.

I'm on BES and when I go into my email and choose compose, it says it's sending from "Default". but if I type in an email address that isn't in my contacts or maybe my BES contact list, it then switches the from field to my blackberry address.

Does anyone know why this is happening and how to stop it?