Boy this was really annoying to me because since Snow Leopard, FileMaker has not supported long names in Open Diretory for authentication. This was never a problem on the Active Directory (Windows) side of things, but it did not work all through Lion (OS X 10.7). But with the relase of FMS 12 v2, one of the items it says they have corrected is the ability to use the Open Directory long names for LDAP authentication. All of my users had been using long names for accessing file sharing and other OS X Server services and then Lion came along, they had to switch to their short names, which many did not know what their short name was.
For those who do not know, the Long Name is the field that allows some special characters (e.g., space) in them so that your User ID could be something like "John Doe". But Unix requires a unique short name meeting certain rules and when you name someone "John Doe" in Open Directory, it gets a short name assigned that is something like "johndoe". Most LDAP accounts have both a long and a short name. But often the long name is easier for people to remember. With FMS 12v2, FileMaker can now authenticate to either the long or short name.