First of all we suggest that you consider whether you need to offer payments with Postcard at all. More or less all Postcard holders do have the possibility to use other Payment Methods they hold as well. The reason to consider this is that Postfinacne charges extra monthly subscription fees for their Accounts.
Anyway if you choose to connect Postcard as a Payement Methods, there are several possibilities for that. Currently Postfinance offers these 3 possibilities:
It depends on your requirements what Postfinance Account Type you want to integrate to Payrexx, all of them are possible.