Invoice number on the invoice.

Sure! Check out this post for instructions. For this solution to work (not display the order number twice), you need to set the plugin to use invoice numbers.

Let me know if you still have any questions.

Have a great day!
Ewout

hello Ewout, thank you for yoer plugin ??

i have tried the way that you linked, but in my invoices is now not the invoice-number displayed, its a second order number.
also is the number in the invoice-pdf-name the the order number.

a screenshot is here:
<img>https://dl.dropboxusercontent.com/u/2455851/pdf-invoice.png</img&gt;

plase help me!

ok, problem solved: it must set to “Built-in sequential invoice number”.

and here are corrected DE language files

https://dl.dropboxusercontent.com/u/2455851/WooCommerce_%20PDF_Invoices_Packing_Slips_DE.zip