I think you first have o have it hosted somewhere (you probably have this covered). Next, go to your vB home (profile), select edit options at the top, then scroll down and click change avatar. Down in the bottom is a section that says Custom avatar, make sure that "yes" box is checked, put the url to your hosted avatar and click submit modifications. The rcnt server will access the url and put the pic in our database (it'll load from here, and not where it was loaded from). That should make it appear under your username.
Welcome to the avatar club Team 17!