I want an option in a certain payment module for oscommerce.

The module is already there But needs a modified clone which will have the abilty to prepay a certain amount depending on the order ammount, so that the rest ammount is paid on delivery to the driver or postman.

0-100 euro is prepay all
100-500 50% prepay
500-1000 40% prepay
1000-2000 30% prepay
2000 of meer 25% prepay

Example:
i order a product with 600 value, i have to prepay 40 percent =240 euro, restammount of my invoice will be 600 - 240 = 360 euro

the used module is IDEAL for the Nethelands only.