Dan,

>BindingSource = UnitsOfMeasure (this is the lookup table business object)
>BindingSourceDisplayMember = cDescription
>BindingSourceValueMember = cUnitOfMeasure
>BindingValueSource = CommodityCode (source table business object)
>BindingValueSourceMember = cReportUnit
>
>
>On the form, the UI displays properly, the combo is being populated properly. When I select a value, it is not being written back to the business object. When I try to save, the cReportUnit field is empty. Again, this happens with both the MM.NET ComboBox and the MM.NET Infragistics UltraCombo controls.

cUnitOfMeasure and cReportUnit are the same data type, right? If you're working with mmWebCombo you can set a breakpoint in one of the BindBackListValue() methods to see what's happening at run time.

Best Regards,