This topic is not a bug report but a feature request.
The "so-called" invoice we see in Woocommerce 1.3 admin area and the customer e-mail is a half-completed invoice. It is an order detail instead. Many information are missing. It must follow some basic and mandatory rules:
A real order must have the complete name address, phone, e-mail of the shop and customer, some legal text and registration numbers for the shop usually found in foot page (the content depends on what the country is asking for), the date of the order, a unique and incremental number for the invoice, description - quantity - unit price - amount of the order, handling fee if any, discount if any, shipping fee, total tax free, amount of tax, and grand total. And a comment or special instruction field would be great to put special information.
I don't use Woocommerce today because no serious invoice is edited. If it is not in pdf format, it can be in html, in a way to print it or do a pdf ourselves.
Please, update you very good plugin. Or, if someone can code an extension, that would be great.