Using the References Association with a Class mapped with Where

[sternr]

I have a legacy table storing multiple types of lookup objects, here's the table description:

T_Lookup{ Id (key), object_type, object_id, description}

Where Id is table key and the object_id is the unique key per the object type.

All other tables use object_id as a foreign-key column and have no direct use of the id column of this table.

So I tried mapping a Country lookup class from this table using object_id as the key column, and defined the following where: "object_type=10".

While this works for direct queries, when I try to query over a different class that has a references association to this Country class it failes.

Looking at the sql the query generated I see the Country where (object_type=10) is not used hence the association is not unique.

Does the where attribute support associations? if so, what is the right way of doing it?

Thanks!