Manual pegging of Purchase order wich is created by a Distribition order

Dears,

I want to peg a costumer order with a purchase order. However, the purchase order is generated by a distribution order.

Is this possible? The help function tells me that “Furthermore, only the purchase order lines that can be manually pegged are displayed, i.e., those with the demand code Inventory Order”

In this case, the demand code of the purchase order is ‘Distribution order’. Does this mean that I cannot peg?

Thank you!