Fully qualified domain as CNAME name?

[meloncholy]

I'm trying to set up Google hosted on a domain, so I've added CNAME records intended for mail.mydomain.com and googleverificationstring.mydomain.com

The problem is that the main domain associated with the hosting package is my-domain.com, whereas the domain we actually use is mydomain.com (I don't know why it was set up like this.) So I can go to mail.my-domain.com thanks to the CNAME I added, but mail.mydomain.com doesn't work. The host doesn't seem to offer any way to configure the DNS specifically for mydomain.com

If it's useful, here is what I added

googleverificationstring CNAME google.com.
mail CNAME ghs.google.com.

Is it possible to use a fully qualified domain as the CNAME name? Could I add

mail.mydomain.com. CNAME ghs.google.com.

Or is there something else I should do instead? As you've probably gathered, I'm pretty new to all of this and I'd be grateful for any help.

[2lame2rank]

You should contact your host for this, it is more a problem with their control panel than anything else. Maybe they can change your primary domain so you can control things.

[meloncholy]

I've already asked them about this, without much success. But I'll try and phrase the question a little more specifically and see if I can do any better. Thanks for your help.