Adding unit_cost fields to orders_products table

I'm running Zen Cart 1.3.8a, Patch: 1::, Database Patch Level: 1.3.8, and PHP Version 5.2.13.

What I want to do is pretty straight forward but I have yet to attempt a modification like this one. All I want to do is add two fields to the order_products table at the time of purchase/checkout...

The unit_cost field from the products table AND the options_unit_cost from the products_attributes table.

I know how to manually add these variables to the MySQL table, but I have no idea where/how to edit my php code to make the auto-populate happen at the time of purchase. Any help from one of you experienced Zenners would be greatly appreciated.

Thanks so much,
-Dan

Anyone? Bueller? Someone easily knows the answer to this. All I'm asking is to be pointed in the right direction. If I just knew where to make these custom mods I'm pretty sure I can figure the coding out for myself.

Thanks in advance,
-Dan

Maybe an FAQ or support thread already exists for the kind of thing I'm attempting to do, but it's proven very difficult to find any existing answers. Again, just a point in the right direction is all I'm looking for here. Thanks.

Wow, no one is willing to help in any capacity? Do I have bad keyboard breath or something? :dontgetit