Using POP to authenticate

According to this page, Web-CAT supports authentication against a POP mail server. It is true that there is a PopAuthenticator class included in the distibution. However, the initial setup for Web-CAT does not allow the selection of the POP authenticator. It only allows the selection of the built-in database, an LDAP server, or a custom class.

I know that I can enter org.webcat.core.PopAuthenticator as a custom class, but I'm not 100% certain what changes need to be made to the Web-CAT configuration file, and because the UI does not allow me to specify the additional parameters for the POP server, it can't actually make it past the final stage of the installation setup to be able to authenticate the admin.

Can a developer or anybody with experience using POP authentication give me some insight into how to configure this properly? I'm extremely excited to make Web-CAT available to my students this semester (I have 155 of them spanning freshman through junior programming courses) and it would be most convenient if I can authenticate against our existing user accounts instead of manually importing everybody. (I don't think LDAP is available to me.)

Thanks for any help!