From the perspective of your loyalty integration there are three ways to pay:
only by secucard;
only by credit card, or SEPA direct debit;
partially by secucard, and the missing sum by credit card, or SEPA direct debit.
Your system tells our API when the payer wants to use his secucard. In our answer, you see, whether it can be paid with this card, or how much is the missing, that needs to be paid by one of the other methods.