Yes you can, when you order a package from us, enter your domain name in the appropriate field then click Search, click Self-Management, and then click Submit. If you want to still use your own nameservers, then you'll need to just add a few A, MX and CNAME records at your registrar with your given I.P (if you need assistance with this, please submit a ticket). The second option is to let us configure everything for you, you will just need to change your domain's nameservers to ours (see below), then we will be able to set you up quickly.
Our nameservers are:
After this has been completed, it can take up to 48 hours for your domain to point to your hosting account.