Kreditor Invoice and Pre Payment (with Invoice charge) - Sweden
From Zen Cart(tm) Wiki
Kreditor (Sweden) has a Zen Cart™ module for invoicing in Sweden.
http://www.kreditor.se/documentation/
Their solution contains both a Payment Module and Invoice Charge (faktureringsavgift) part (in Order Total).
Download at http://www.kreditor.se/integration/kreditor_zencart-1.15.zip
Seems to work in 1.3.0.1, but needs to be validated.