Add Button/Link to OWA logon page

I would like to add a button next to the sign in button on my OWA logon page. This button would simply be a re-direct to another site running on the same server (Just on a different port)

Example:

mail.mydomain.com (owa logon page)

mail.mydomain.com:8888 (This is where button/link would take you)

How can this be done.

Thanks!