${PREFIX} should work for the admin username

Virtualmin Theme version: 6.4
Virtualmin version: 3.63
Operating system: Redhat Linux Fedora 8
However, it doesn't get expanded so you end up with ${prefix} (yes, mapped to lower case) as the user name.

I would have thought there would be an option to have a default username for the top-level domain (or sub-domains) and that one could set it to ${PREFIX}. I.e. for test.com, the user would be 'test'. For reallyCoolThings4u.com it would be 'reallyCoolThings4u'.