The cXML Purchase order send functionality is based on the purchase order confirmation as we need to have confirmed data to send to the supplier. This video gives an overview of the process of the order confirmations generating either a new, update or delete cXML message to send the purchase order to the supplier.

AX2012 R3.

Refer to this post for an overview of the cXML Purchase Order Send.

cXML Purchase Order Request Send AX2012 R3 V1

Cheers

Lachlan