How do you manage backorder?

How do you manage backorder?

Let say customer buy 10 items, 2 items are backorder.
is there any extension or vqmod that allow to make 2 invoices,
do you edit and create manual invoice

Please share the way you think is the best way to handle this situation.

I'm using OC 1.5.6.4

Any solution is welcome

Thanks
Lenamtl

I added a column to the standard invoice for item status and added status code list to the bottom of the invoice. I manually write the status in on the invoice including B for Backordered, will ship separately.

I also have a order status of "Shipped - Partial" and in the order notes include what shipped for the line with the tracking number, and what is backordered.

Don't know if it's "best"...but it works for me.

In my case the store owner want to charge for every shipping.

Other solution I found is to have a form that will notify the client when the product will be available again.
Or add a pre-order option for BO product, but in that case when the system should charge the client...

What did you end up doing for this?