[TYPO3-shop] Discount implementation

[Markus Friedrich]

Hi list!

I'am trying to configure a discount depending on the carts total amount, 
  I've tried the "discountprice" setting and the calculation with an own 
script, but I wasn't able to implement this:

 >= 150 € => 3%
 >= 200 € => 4%

I would also like to have a single line in the checkout like:
"Discount:	-50 €"

Is it possible to do this?

In my shop there's no shipping configuration needed, so I already tried 
to calculate this discount via a "calculationScript" in the shipping 
area, because there's already a marker in the html template for this. 
This seems to work, but unfortunately this value was always added to the 
payment costs. If there's a way to prevent this behaviour, this method 
would work for me too.

Thanks in advance
Markus Friedrich