Pass nid variable to Ubercart order in D7 How can I pass a node's nid variable to Ubercart so that when the user pays for publishing his node, the nid shows in the cart?

I tried to add a field to the Ubercart Order fields, with widget node reference which is passed by the URL. When my user clicks on "Pay for node" link, it sends him to the Ubercart "node" product page "pay?23" 23 being the node they are paying for. When the user presses Add to Cart, I cannot see this value 23 in any of the user's order or checkout details. How can I get this value attached to the order?

I've googled for a while now and cannot find anything about this for D7. Any help will be much appreciated!
If you are using Cart Links (/admin/help/uc_cart_links), you could pass a value for a text-field type of attribute on your product. 
You'd have to add an attribute to the product node, and hide it via css or form_alter method on the product view page so that they couldn't overwrite it or delete it.
When they add attribute to the cart with the cart link, you can feed in the value with the url parameter like ( /cart/add/e-p23_q5_aThisNiceEscapedString. ).
Note that you can't just pass an integer to it, or Cart Links will think you are passing the AID (attribute ID)