How to display a Manual Duplex Instruction Dialog in CUPS driver

[keens312]

Hello,

I am developing a CUPS driver on Mac OSX (rastertomyhplpj).

There is no hardware button on my printer.

So for manual duplex, a dialog with a button should show up when first half job are printed.

The dialog will show the instructions to users about how to rotate the papers.

When user put the paper back, and press the button on the dialog, the second half job will be printed.

My question is how can I archive this on Mac OSX Leopard?

Any suggestion and advice are appreciated.