Can't set ST_GEOMETRY column to null with JDBC

I've been struggling with using the JDBC to work with spatial types. If I try to insert or update a null value to a column of type ST_GEOMETRY, I get an exception for the form:

Caused by: com.sap.db.jdbc.exceptions.BatchUpdateExceptionSapDB: SAP DBTech JDBC: [3]: fatal error: Execution flow must not reach here. See error trace for details...

Anybody trying to do this?

We are using Rev 73. I have tried a couple of different versions of ngdbc with the same results.