Math operations with new table BOM

This question is regarding the new table based BOM's in SolidWorks 2004. I feel like I'm missing some very basic functionality that I can't believe is not there. All I want to do is in the table BOM on each row take the quantity of parts times the weight of the part. I would then create another column for example called total weight (for that row) and put that value in. I then at the bottom want to sum up the total weight of the assembly.

I understand of course how to do that with the old excel based BOM method. I also understand that I can go into the mass properties of the assembly and check the total weight. I thought that simple math operations would be included in the new table method

Thanks Much