Hi, the help file says the opposite of what is written above. It says to use the original domain name in the redirection field.
I still have been unable to get either one working in 7.x
Imagine that the main domain of your website is domain.com and you have domain.co.uk defined as a domain alias with the Redirect URL field set to:
These macros can be used to dynamically redirect users to the correct page under a different domain.