Instead of removing these info, which is mandatory by the way, I suggest to use the ldap auth plugin and if you like also to have SSO, then combined with auth pass thru plugin.
We also successfully using it that way internally ;)
If your using apache, see my little how to here for apache SSO with osTicket:
http://osticket.com/forum/discussion/comment/82591/#Comment_82591
Cheers,
Michael