Is it possible to create purchase order from a back order?  Tried it earlier today & got the following error message. 

'The order type Back Order, has not been selected as a default setting at the Sales Order Type to Generate From field in Auto Generate from Sales Order, therefore, the purchase order(s) will not be generated for this sales order.'

In house i.t. said it's not possible unless we change the default from 'standard' to 'back order', which we do not want to do. 

Is there a different way to do this other then manually adding the SO# to the PO after it's created & vice versa?