SSL on DOMAIN MAPPING with WP multisite

Hi Guys,
Im running a wordpress multisite and would like to add SSL certificates (to show as HTTPS) to some of the websites in it (with DOMAIN MAPPING). I payed for certificates on ssls.com but I cant find any guide of how to connect the certificate to a mapped domain inside my network. The network has its own IP address ofcourse.
Please help.

Thanks.