How to handle perfoma invoice?

Hi all,

Is there any have experience before and mind to share how to solve it?

1. My client need to print out the performa invoice before job
complete. This perfoma invoice is used for declare custom duty clearing
purpose.

2. Can i use misc. shipment print out the doc?

3. Is there any quantity affect misc. shipment entry?

4. Any alternative way to suggest?

Best Regards,
Admund Ng