Are you trying to set up something like hotmail or yahoo for your BIS account? If so, you can do it at your desktop by visiting your BIS account online. For example, I go here to manage my accounts: https://bis.na.blackberry.com/html?brand=mycingular
Are you near a PC? I find that it is easier sometimes to edit/make changes to my BIS account from the PC than navigating thru the BB. Hope that helps.