SBS 2008 setup

Hello everybody

I have a question, I recently installed my SBS 2008. Everthing is working, beside my exchange part of the server. If I try sending mails out, they don’t go anywhere, and I also don’t receive my mails. If I do an nslookup, the message comes back, that my name server failed. What did I due wrong? My domain name is hosted by canaca.com, do I have to change the name server entry on there end under my domain manager, or do I have to add there name server to my DNS? It is the first time I am setting this up on my own, and I would like to be able to handel that myself. Can anybody give me some advice on what I have to check, or maybe what entry’s I have to change.

Thank you in advance for all your help.

Cheers
Oliver