Ubercart

Currently I am working in Ubercart 2.x
I have made the invoice to sent when the customer buy's the product and after checking the payment received. But I need to change it as per my project scope as the invoice has to be sent as soon as the product got expired(Executed this feature with the help of Limited Time Offer module). So need to send invoice once the time expires.
Please suggest me how to edit the Store Administration -> Conditional Actions to perform this one.

Your kind help will be highly appreciated.