custom invoice number printed

helo,
i have this module : http://www.opencart.com/index.php?route ... earch=uber

and i select which invoices i want to print to google cloud print.

but now i needs to appears invoice number (not order id), but to count it only for orders i click to print and not count it for all orders i receive to my shop.

for example i have 5 orders. and i want to print the first and the fifth order, i want the first order to take invoice number 1 and the fifth order to take the invoice number 2.
and later if i print another order, automatically takes invoice number 3 etc...

thanks,
alex

alexgthess wrote:...and i select which invoices i want to print to google cloud print...

So I assume you are already using google cloud print with opencart ?

alexgthess wrote:...for example i have 5 orders. and i want to print the first and the fifth order, i want the first order to take invoice number 1 and the fifth order to take the invoice number 2.
and later if i print another order, automatically takes invoice number 3 etc...

So the script has to check whether the print is successful or not too ?