Multi-site with Multi-domains confusion

I have been trying to get my multi-site network to work using multiple domains that are on the same server.
My provider has it setup that sub-domains are in the public_html\ directory, also they are automatically given subdomains under the main domain. So html content for a subdomain can be accessed by using
public_html\subdomain.com, or subdomain.com or subdomain.maindomain.com.
So, I set my domain wildcard to *.main domain.com and pointed it to public_html\. I can create my multisite just fine when using the main domain.com.
Now for the tricky part. for my subdomains.. do I use a wildcard that points to public_html\ or public_html\subdomain.com.?
I have tried every which way to get this to work on a single multisite install, to no avail..
Does anyone have a solution that works??