Hi, looking here we founs some tips about godaddy.
http://help.godaddy.com/article/679
So:
Enter an Alias Name = your subdomain if you want to set up something like: webcam.yourdomani.com or www if you want to setup it up on
www.yourdomain.com (remember to add one more CNAME record with this field blank to be able to use yourdomain.com (with no www) as well)
Points to Host Name= just enter yourlogin.rivcash.com where yourlogin is the rivcash username you use to login to control panel.
When done and when Dns are updated, just go to Rivcash controlpanel and set up a new site.