unsaved-value="undefined" not working?

[Steven]

Hi,

I have a mapping with a timestamp column that get's set to null via a legacy process (that I can't touch) which later causes my app to error with the stale data exception.  I've tried to set my unsaved-value="undefined" but the generated update statement still tries to check for the Timestamp. I'm using FluentNHibernate v1.3.0.717

relevant map

    <id name="Id" type="System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" unsaved-value="0">

      <column name="FTS_VENDOR_STORE_ID" />

      <generator class="sequence">

        <param name="sequence">Vendor_store</param>

      </generator>

    </id>

    <version name="TimeStamp" type="System.Nullable`1[[System.DateTime, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" unsaved-value="undefined">

      <column name="TIMESTAMP" />

    </version>

generated sql

WHERE FTS_VENDOR_STORE_ID       = :p45

AND TIMESTAMP                   = :p46;

Any help would be greatly appreciated.