We're doing a Commerce implementation with multiple warehouses, and we've created a custom IFulfillmentWarehouseProcessor as per the suggestions in this article: https://support.episerver.com/hc/en-us/articles/115003636971-Commerce-CheckMultiWarehouse-implementation
This works fine on the website, with cart validation etc. through the API.
However, in Commerce Manager, I get the error "Multiple fulfillment centers without custom fulfillment process." when I try to change and save the order.
I've tried registering the custom IFulfillmentWarehouseProcessor in the Commerce Manager project both with the ServiceConfiguration attribute and by creating a Commerce InitalizationModule and registering it in the ConfigureContainer-method, as such: context.Services.AddSingleton<IFulfillmentWarehouseProcessor, CustomFulfillmentWarehouseProcessor>();
When debugging, the custom implementation never gets invoked, although I can verify that the InitializationModule runs as expected. Commerce Manager just uses the default implementation. Am I missing something here?
Commerce v.11.8.1
