That is the problem, because Hotmail is web based email that doesn't use the standard SMTP protocol but a propriatary MS protocol so Outlook can send to it, but avast can't handle that protocol.
So you would have to start by creating an email using Outlook to virus@avast.com, zip and password protect the sample, then send it to avast.
Another problem that I foresee is that although zipped and password protected Hotmail may block the sending of the email because the Ravenhearst.exe is an executable file and whilst it can scan the file it blocks by type a really crude and pathetic strategy. So before zipping the sample you may need to rename it Ravenhearst_exe.txt as that file type shouldn't be blocked.
Whilst this is a lot of hassle it might be the only way of getting past Outlook and Hotmail to submit a sample. There is no such problem if you had a conventional POP3/SMTP email account (like one provided by your ISP, etc.) then it could have been sent from the avast chest, no zip/password hassles.