I dont know the 'IDeal' (dutch?) payment system. Does anyone know if it is difficult to get it to work to work with bda.plone.shop?
Maybe take a look at this payment integration to get a clue how to implement it:
wallee is in testing still... but similar and based on GitHub - bluedynamics/bda.plone.stripe: Stripe payment integration for bda.plone.shop
I haven't worked with 'shops' for 3 years, so I dont remember too much, but I assume it would be a bit of work to the IDeal payment 'up and running' (?)
I would be a 'sub-contractor' for this job, so I might 'leave it to someone else' (if anyone is interested I would pass it on)
The shop side is not a big deal...
The big deal is always the provided api and foremost docs... of payment service
I googled Stripe, and it says it supports IDeal ( https://stripe.com/docs/payments/ideal ), so maybe that is an option ?