Redirect domain to sub-domain?

So I have a sub-domain set up at Dreamhost (tm.sans-concept.com). All I want to do is point a domain that I have registered elsewhere (in this case, Dotster) to that sub-domain. I can’t seem to find any info on it though. Help would be greatly appreciated. Thanks!

Go to Dotster and set that domain’s DNS servers to ns1.dreamhost.com, etc.

Then go to the panel and select Manage Domains to add a new (sub)domain.
https://panel.dreamhost.com/index.cgi?tree=domain.manage&

Pick the Redirected form and put otherdomain.com to Redirect to http://subdomain.yourdomain.com

-Scott

Thanks a bunch!