[TYPO3-commerce] Manual for implementing payment methods

[Andreas Kiefer]

For an upcoming project I would like to use commerce as shop solution. 
For this project I need to implement worldpay (http://worldpay.de/) as 
external payment provider. I wasn't able to find a tutorial or some 
hints to do that yet (hope I wasn't too blind). Is there already 
something like a tutorial or could you please give me some hints how to 
do that?

Thank you in advance,

Andreas