Retrospective pegging of a Purchase Order to a Sales Order

For new parts the Items and Production BOM are on NAV but often, the purchaser will purchase the materials before the routing has been set up in NAV.

This means we can not use order planning to generate a Production Order yet and therefore can not produce a Purchase Order using Order Planning based on Production Order demand.

The Purchase Order is placed manually.

Is there a way to specify which Sales Order the purchase order is for?

and, after the Routing has been entered into NAV, is there a way to specify which Production Order that the Purchase Order satisfies retrospectively ?

Using NAV 2013. (soon to upgrade to R2).

Thank you

Dave K.

I also note that the Purchase Order line has a Production Order No. and Production Order Line No. field.

This would be great, only I don’t seem to be able to update these fields even if I Re-open the purchase order.

Any one know why?

Thanks

Dave K.