Invites by User Name

[kau]

Is there a stock way to invite people to a forum using your user name instead of ID?

Example:

Default:

http://www.coffeeforum.com/forum/register.php?referrerid=1

Is there a way to do like:

http://www.coffeeforum.com/forum/register.php?referrerid=kau

Tried the above but that didn't work.