Simply request to make independent {order_sale_date} (date of sale on).
in 99% cases the date is the same as invoice date but some times, when customer make the bank transfer for his own the difference between order_sale_date and invoice date (date of posting the money on my account) can be even few days (weaks if some one forgot).
Besides most invoice in my country (Poland) have date of sale and invoice date (to be honest I don't know if that has to be by the law or not :) ).
I tried to reprogram that by my own (trying to add {order_sale_date} replacement field in php and db) with no luck :) .

And the second thing. Is there any chance to make {total-words} in polish (or any clue how to make it)?
Thanks in advance.

Lorenc Bartosz