If I use
postfixadmin-cli alias add email@example.com firstname.lastname@example.org
I get an PHP error:
PHP Fatal error: Call to undefined method AliasHandler::add() in /usr/share/postfixadmin/scripts/shells/alias.php on line 107
When you reported the bug, this was not implemented yet.
I worked on the *Handler classes in the last days, which means this is fixed in SVN trunk r1364 :-)