I am building a fulfillment service and want to create some test orders via the REST API to test the workflow. I am following the instructions here to create test orders and transactions: https://shopify.dev/api/examples/order-testing
The orders are being created successfully but instead of being associated to the fulfillment service they are associated to the store's default location - even if the products on the order are all setup to be fulfilled by the fulfillment service. There is no fulfillment order object created for the order and there is no option to "Request Fulfillment" in the Shopify Admin web portal.
If I create an order for the same products via the Shopify Admin website, then a fulfillment order is created at the same time which I can retrieve via the API or Request Fulfillment through the web portal.
How do I create orders via the REST API that have associated fulfillment orders which I can then assign to my fulfillment service?