Maruthi,
If I were you I would recreate the stack file with the Add-on and start the EHP7 update from scratch with a newly extracted SUM. You are just in the "Configuration" phase so you can easily do this. If this is a sandbox system you may select the options provided (preferably 1 or 2) and see how the upgrade goes. I believe the option 2 (Keep the add-on) will prompt for a vendor key.
Regards
RB