BetterNow has a direct integration with Vipps and is an official Vipps partner.
To set-up Vipps through BetterNow you will need to
1) Create a new "salgssted"
2) Pick "integreret betaling" as the product
3) Here choose that you will be seeing the product on your own homepage and then choose "Betternow Worldwide ApS" as the partner who will be implementing the solution.
If you can offer donors tax deductions, then ensure that Vipps has you approved for collecting "fødselsnummer" via Vipps.
BetterNow will then be notified about this as soon as your order have been approved by Vipps.