I have a multi-database application configured with NHibernate. The entities that correspond to tables from each database are in their own separate assemblies (an assembly per database if you will). I have a need/desire to relate an entity from one database to an entity of another database. Everything up to this point works as I want it to (the application handles multiple session factories, etc.).

The relationship I want is many-to-one, but in reality my application only cares about one side of the relationship (for reasons that aren't relevant). The relevant entities are Project and PMProject, where a Project HAS A PMProject. When I map the many-to-one, I get the following error:

NHibernate.MappingException: An association from the table PROJECTS refers to an unmapped class: SDMS.PPRM.PMProject

The Project mapping itself reads (ignore the funky column naming; it's an Oracle db):

<many-to-one name="PMProject" class="SDMS.PPRM.PMProject" column="PM_PROJECT_ID" cascade="none" />

In the class attribute, I'm referencing the appropriate assembly, but I get that error which seems to tell me it simply can't find the mapping file for PMProject. But that file exists (it's set as embedded resource), the session factory instantiation works without fail; so I'm at a loss on how to tell the Project mapping how/where to look for the appropriate mapping. Is there something I'm missing? A better way to go about this?

Thanks in advance.