[Klarna] How to enable «B2B» for a Checkout v2 merchant account?

The documentation for the «allowed_customer_types» order request field says:

List of the allowed customer types.
Allowed values are ‘person’ and ‘organization’ if B2B is enabled on the e-store ID.

https://developers.klarna.com/en/se/kco-v2/checkout-api#options-object-properties

So how to enable «B2B» for a Checkout v2 merchant account?

I have got an answer from Klarna’s support:

The merchant needs to sign up using an onboarding link they get from their partner.
The partner needs to integrate the B2B functionality, and get it verified by Klarnas integration department before any customers can apply.

For testing purposes. I have enabled B2B on your testdrive account.