How to use auto generated ID in Main Form to subform.

How to use auto generated ID in Main Form to subform.

Hi
I have created two forms Shipping and Product Info. Product info is the sub form in Shipping Form. when I submit the form then two reports are generated which contains the Forms details and a auto ID is generated.  I want to know can I used that auto generated ID into sub form to create the relation between main form and sub form ?