Can I install Prosites on a subdomain?

Hi

I have only one question.
Is it possible to install Pro Sites on a subdomain, and then give users when they signup a subdomain, too?

Like
myprosites.domain.com <--my Prosites
client.domain.com <--client

Possible, or do I have to do it like that:
myprosites.domain.com
myprosites.domain.com/client

Thx for your time.
Silvio