Using Hibernate 2.1.6.

I've got a legacy database (that I can't easily cleanup) that has null-value keys mapped as '0's. Hibernate rightfully complains when it tries to build the associated object based on what it thinks is a key of 0:



I think I'm supposed to use a UserType to get around this, but I'm just not certain how.. can someone give me the high-level view of how a UserType would work here, since the Integer maps to an object that needs to be retrieved?

thanks..