Here is what I do:

Login with the Host Account
Go to Host Settings
Use the Other Settings tab
Enable Request Filters
Add New Rule

Server Variable = “HTTP_HOST”
Operation = “Equal”
Match Value = “<old URL without http://> IE: OLD.DOMAIN.COM
Action = “PermanentRedirect”
Location = “<new ULR with http://> IE: http://NEW.DOMAIN.COM

This takes any request for the OLD URL and redirects it to the Home Page of the NEW URL.  Maybe a litte different that what you are wanting.  I do not know if you can adjust the Location value to include the part of the OLD URL that targets a specific page.

Thanks,
Greg Hart