domain name system - CNAME help - wildcard DNS for SaaS

I am trying to figure out how to allow my users to use a CNAME for their unique wildcard domain. (user1.wlapi.com), etc

I read here: https://stackoverflow.com/questions/5101195/custom-subdomain-with-cname-problem

That using a wildcard DNS for CNAME's may not be the best, so I would need another way to identify the user, thats fine. I can do that with some database work.

However, I can't seem to get the CNAME to work with user1.wlapi.com OR wlapi.com

It just doesn't do anything... just loads up a blank screen.

Question:

What do I have to do to allow for CNAMES to work on my server? (I am using MediaTemple, but I can switch if there is an easier host for this)

I read something about .conf files with VitrualHost but that doesn't make any sense to me...

Update

I got it working! I upgraded to dedicated server with a unique IP, and that seem to work.

The wildcard DNS does not work, but I can I just use the HTTP host to find the user. :)