Pointing hosted domains at CCGI

[#1]

I now have a domain hosted by PlusNet, and it's successfully pointing at a folder below my htdocs on what I gather is called the Homeserver site (www.username.plus.com). I gather that it's possible to point the domain at the CCGI platform instead (again, at a domain-specific subdirectory under my space there), but I haven't yet managed to find details of how to do that. Can someone steer me in the right direction please?
Thanks.

[#2]

You can't point a domain at a directory on CCGI - you have to fake it with htaccess rewrite rules.
http://community.plus.net/forum/index.php/topic,46224.0.html

[#3]

Thanks for that. I saw a mention somewhere about creating a CNAME record pointing www at ccgi.plus.net, but I thought I'd need an A record too, and I thought I would need something else to specify my space on the server rather than the server itself (I still don't understand why it's not possible to simply point it at ccgi.mydomain.plus.com, but...). Presumably that's what this bit is about:

Quote

Then I raised a ticket with PlusNet Customer Support to ""Change the CGI service to basic" (this will create the necessary records on the CGI and DNS servers to correctly point the domain to your files on the CGI server.)".

... which I hadn't seen mentioned anywhere else. So I have to raise another ticket? Sheesh! Why isn't this done as part of the original transfer in when (presumably) the same kind of changes are made to the homepages server?
Also, I note from one of the tutorials referenced in that thread that "keeping your whole website on the CGI server" is not recommended. Why is that?