To answer my own question after working on this for 2 days is: I don’t need another payment button.
The Account Transaction Type defined in payment types is the same one I need for the Discount transaction.
There is a “Pay Ticket” action in the Rules when Payment type is selected (as per the Q’s tutorial). I put a constraint to select which Action to use based on an Entities Status.
There is a “Create Account Transaction Document” action used in a rule after a payment is processed (again, as per Q’s Tutorial). I also constrain the rule based on Entity Status.
