How to make a simple payment module

[depsibob]

Hi all,

 

I'm setting up my osCommerce 2.2 and got stuck in payment modules.

I need to create a simple module that adds an fixed amount on an order + tax.

Need to do it for the Swedish "postf?rskott" payment type.

 

Has any Sweed in this forum done this allready or is there anyone who

knows how to make this module?

 

I have looked at the other payment modules, but can't figure out how

to code this one.