How To Update New Orders_Products Field?

I recently added a new field to the zen_products and zen_orders_products tables called "Products_Secondary_Model". My goal is to have the zen_orders_products table updated with this field after an order is placed, just as it gets updated with the regular products_model field by default.

I cannot see where this information gets updated into the Zen_Order_Products table (or if I do, then I cannot get my value to stick). The only thing I can find is in the order.php file (located in includes/classes/), where it says this:

      $sql_data_array = array('orders_id' => $zf_insert_id,
                              'products_id' => zen_get_prid($this->products[$i]['id']),
                              'products_model' => $this->products[$i]['model'],
                              'products_secondary_model' => $this->products[$i]['secondary_model'],
                              'products_name' => $this->products[$i]['name'],
                              'products_price' => $this->products[$i]['price'],
                              'final_price' => $this->products[$i]['final_price'],
                              'onetime_charges' => $this->products[$i]['onetime_charges'],
                              'products_tax' => $this->products[$i]['tax'],
                              'products_quantity' => $this->products[$i]['qty'],
                              'products_priced_by_attribute' => $this->products[$i]['products_priced_by_attribute'],
                              'product_is_free' => $this->products[$i]['product_is_free'],
                              'products_discount_type' => $this->products[$i]['products_discount_type'],
                              'products_discount_type_from' => $this->products[$i]['products_discount_type_from'],
                              'products_prid' => $this->products[$i]['id']);
      zen_db_perform(TABLE_ORDERS_PRODUCTS, $sql_data_array);

As you can see above, I added a "products_secondary_model" field, but when the order is placed, this value is empty in the zen_orders_products table. However, this value does exist in my regular zen_products table where I have defined a secondary model field and placed values in there.

Flow I need: Exists in zen_products --> customer purchases item --> put this new field value from zen_products into zen_orders_products

So my question is, where in the code does the orders_products table get updated where I can insert my products_secondary_model value which exists in the products table? This should mimic exactly what happens when the regular model number gets updated into this table during a normal order checkout.

(I am using the latest version of ZenCart).

No responses? If my question is confusing or you need some more information to elaborate, please let me know. I would like to see if I can get this to work though soon.

Again, I think it's as simple as helping me find which function inserts data into the Zen_Orders_Products table, and how to put a custom value stored from the Zen_Products table into that field.