Manually assigning a UC node to and order

Could anyone give me a head start on how to link a uc node checkout node to an existing order? The use case scenario would be an order generated on the phone which then needs to have a nc nodecheckout node manually created by admin and then linked to the order. I was thinking along the lines of a CCK field which contained the order id. When the manually created node is saved a hook could be used to update the uc_node_checkout_order_products table. Not sure which hooks. Does uc_nodecheckout have its own? Which is the function called that associates the node with the order id?

Many thanks in advance.

Ryan