how can I prevent the worker from inserting an item in sales order has no quantity

hello every one I have a question need your advice please, our selling method based on sales order, some items has no quantity there but the salesmen are able easily to insert the item on sales order then sell it! (before invoicing)

although the item model group is FIFO and I already stop physical negative inventory there, these option is working fine if they want to invoice the SO , the system will not allow them to invoice any sales order has zero on hand quantity , but I need to restrict the sales man first from choosing any item has zero quantity .

is there any option to do so on AX 2012 FP

any reply or help would be highly appreciated

You can’t prevent entering the item with no on-hand quantity into sales order in the standard AX as far as I know. However you can keep a validation for the same through small customization in SalesTable, SalesLine table related methods.