Losing 'Other...' login option on OD master
I have a mac mini running Lion Server which is an OD master. It is setup to authenticate against it's own OD service. However I can only do this when the machine first boots up. If I go back to the login window after the first login event, either logging out or using the fast user switching menu, the 'Other...' option dispears leaving me with option to login as the local admin & the currently logged in network user (if a network user is logged). I can't find any reason for this behavior & in all honesty I have no idea where to start looking to solve this problem.
A possibly related thing is I'm currently unable to get a ubuntu file server authenticate against the OD server. However, I've not put any effort into fixing this as it's not a serious problem.
Mac mini, Mac OS X (10.7.3), 2.7GHz i7, 16GB ram, 2x 512GB SSD