include coupon code in $0 initial invoice for free trial order

include coupon code in $0 initial invoice for free trial order, along with the trial: and payment plan: Only need the coupon code used so there is a record of the options selected when placing the order instead waiting until the first payment to see the code.  When I see an order comes in I would like to know if a coupon code was used. I have a 2 or 3 week free trial and I don't know if they used a coupon code until the first payment. If i get a call to see is a coupon code was selected I don't know until the first invoice is sent.