Go to hotmail, and if you know how to send from blizzzard there, just copy/paste.
Go to new in your inbox.
Where it says from, go to add an email address.
Choose a blizzard email you think they don't use, like [email protected]
After you send it, go to your inbox. It will say some crap, scroll down and verify it's urs. Now you can send emails from there.