Thanks sreddy. Here is what in export views:

u$.name not in ('ORDSYS', 'MDSYS', 'CTXSYS', 'ORDPLUGINS')

However if try to export with UID=MDSYS it does something, even writes DBM file but with warnings.
(Of course OO stuff is not supported well by Oracle. To move SDO application from one DB to another is really a hedache if have no special scripts.)