Where do you put the Customer PO No.?

In Dynamics NAV 5.0SP1, the caption for Your Reference has been changed to Customer PO No. For us, we’ve always used External Document No. to store┬áthe Customer PO No. on the sales order.

It’s obvious that the change in 5.0 SP1 was done due to┬ápartner requests. I just want to get your opinion on where you put the Customer PO No. when entering a sales order. Please vote here: