I do not think the university has any deal or contract with Microsoft that would require you to use a specific log in or e-mail address. That being said, I would advise you to use your COM address since it sounds as if you are intending to use the program for school work. Since you said you have set one up, I think it would be convenient to use it for the address for the link. Is there a reason you hesitated in using it in the first place? I hope this helps. Please let me know if you have any other concerns, and I can see what I can do to find the answer for you.
Your COM Reference Librarians