Shouldn't receipt include e-cert redemption?

Recently I booked a $500 ticket using a $300 e-cert. E-ticket receipt shows the $200 addcollect for the difference, but has no notation (that I can find) indicating the e-cert amount, number, etc.

I canceled this ticket, and will be able to use its value toward another one (UA was kind enough to waive the change fee for unrelated reasons), but I'd like to have some documentation of its entire value, for my records. Any suggestions as to where I can find it?

Thanks!