Yes, you can. If you already own your own corporate domain (i.e. yourcompany.com or yourcompany.net), you can still use ScalIT. You will just have to modify your domain’s MX records to point to the appropriate ScalIT mail server and web server. ScalIT will provide you with those settings. It is just that simple.
If you do not already have a corporate domain, ScalIT will help you acquire one, configure it, and manage it. The cost of obtaining a domain and keeping it renewed is included in the many services ScalIT provides.