I am just wondering, for example if I buy the domain www.test-test.com and redirect it to my trap17 site will I still have the subdomain I signed up with?
So just breaking it down:
test-test.trap17.com *Before
then
add domain www.test-test.com
can I still access my website using test-test.trap17.com?

and second question, can I use two domains and redirect them both to my trap17 site, so for example I have two domains www.test-test.com and www.testing-testing.com can I redirect then both to the same trap17 website?

not saying that i will be doing this (domains are just getting more and more expensive by the yocto-second...)

Yes, you keep the subdomain as long as you add your new domain as a parked domain. Once you have registered your domain and set the name servers, go into cPanel and find the Parked Domains button. Hit that and then tap your new domain into the box. Click Add and wait a few seconds, and it should work To confirm, both of these links go to my website, which is set up in that way: http://www.rvalkass.co.uk and http://www.rvalkass.trap17.com/



Yup, just park them both using the method I (briefly) described above. As far as I am aware, cPanel limits you to 9 parked domains by default, but I am pretty sure you could get that increased if you really need to.

Also, just so you're aware, on the Parked Domains page of cPanel, you'll see this message:


Ignore it, it's wrong.

If you park the domain test-test.com over test-test.trap17.com, both will work . If you park testing-testing.com under test-test.trap17.com then all 3 domains will work..

but for all 3 to work the primary/main domain has to be test-test.trap17.com. Otherwise you can have test-test.com as the primary domain and all the other as parked domains except test-test.trap17.com

In short.. If you want test-test.trap17.com to work, you have to have to have test-test.trap17.com as your primary domain.