One of the most frequent requests I get from users with Exchange, is to be able to send from one of their alternative email addresses, that is one of the addreses there account is configured with in Exchange, but that is not their primary address. Unfortuantely as far as I am aware Microsoft have not yet come up with a solution to this.

I've used a number of hacks to get round this, sepearate accounts with POP3 access, Using the from field in outlook, but each have there draw back. What have you used in these situations to allow the use of these alternative addresses?