Deposits at POS

[Michael_George1]

Not certain if this is the right place or not for this....  When at a tradeshow, I will take orders for custom products.  I have been having the customer create a form at POS will the relevant information needed for the order.  I created a product called CUSTOM ORDER DEPOSIT and would select that option at the POS for the deposit I require.  After the product is created I have ben invoicing them for the balance by simply creating another invoice.  

Is there a way to create a single invoice at the POS for the total amount and then accept a deposit?  I have been using my process because that was the only way I could come up with to expedite the ordering process at a show.  The final invoice I send for the balance includes shipping charges because when creating the invoice I enter their shipping information.  Using this method, doesn't require me to enter the information at the time of sale which is a little faster.

Thanks in advance for any help.