How to add a shell option for SSH access

[ElmerC]

How do you add another shell as an option to the pull-down menu for granting users access to the server over SSH? The shell is listed in /etc/shells but that doesn't seem to do it on its own. As a matter of fact, /etc/shells lists 16 available shells but the pull-down in the Panel only lists 9.
The shell in question is scponly which was installed from the distribution repository.

Thanks.