I found this over on StackOverflow:
Fluent Nhibernate - Generate a non-primary-key sequence generated
value
http://j.mp/h0wr3h
.. which indicates the only solution might be to hook into
OnPreInsert, making a standard query to invoke the sequence and get
its value.
Is this really the best I can do? Seems like waste to make an extra
database call on insert ...