Adding foreign key field from gridview

[geo039]

I have a gridview with add functionality embedded in the footer row. My problem is I have an id field in the table that is foreign to another table since I cannot add a record with this id field as a null I've been trying to figure how to get this to work. This grid is already populated from another grid's select based on their related id's. I can manually type the id (did to test). I've tried to bind it to a label so it takes it with the other add items but it won't bind. I've experimented with a hidden field but I'm not sure i understand it.

Can somebody help me?

Thanks