Point subdomain to other ip server from sentora

[Ron-e]

First of all, instead of playing with the code, read the docs.

Maybe a good idea to make a special doc for to use a subdomain from another server, or add it to that doc page?
I thought shared domains ware for sharing domains between users on the same server only.
I did not have to use the shared domain option to enter a subdomain in the domains module.