LDIF editor and import don't allow attribute names with an underscore, for example:
The underscore is not allowed wrt RFC 4512. However many directory server implementations (DirX, OID, and various virtual directory servers like SAP VDS) allow underscores. It is not possible to edit or re-import exported LDIFs from those servers. See also
DIRSTUDIO-378 where the underscore wasn't allowed for returning attributes in the search dialog.