domain mapping - map domains using cPanel on the same server

Hi

I have the following scenario and requirements:

Multisite installation and domain mapping installed on eg. domain.com/site
I have additional sites installed in subfolders. eg. domain.com/site1 etc
I have a domain with it's own cPanel, residing on the same server as my multisite install, that I need mapped to domain.com/site2. How do I do this without having to move the domain or cancel it's cPanel account?

I look forward to your reply.