Trying to add alias to outlook.com, getting error

Whenever I try to add an account alias, using my email address, I get this error:

This email address is already taken. Please try another.

I had originally had a separate skydrive.com account that used my email address, but I deleted it (accidentally) trying to merge these two accounts together.

I really prefer to keep the other account and have it re-opened, but if all is gone, I'd like to be able to add it as an alias to this account.  How can that be done?