Can’t Create Purchase Order from Sales Order with Service for Resale Item
The setting for “special order item” simply indicates that every time you have a sale for it, the system will generate a PO for it. However, I have bad news. The ability to auto-generate the PO for a service item for resale doesn’t exist. Please see this article.
If it was me, I would just create a non-inventory item for resale and name it “service item”. Non-inventory items for resale and service items for resale are not the same… but they have a lot of similarities.