In this case you have to use cPanel's feature called "Parked domain". TVMserver allows unlimited number of parked domains which you can point to your primary one.
To access the Parked Domains feature, click on the corresponding icon located on the main screen of your cPanel interface.
To add a parked domain, enter the name of the domain in the blank field and click on Add Domain. (Make sure to register the parked domain with a valid domain registrar and set the nameservers properly or else it will not work)