[TYPO3-shop] How to create a new marker

[Leen Strijk]

I need a new marker in the template that will be used as safety for the 
payment process.

It would be like ###SECRET_KEY###

This value will be sent along with the other data to the paymentserver.

The value will consist of :
MD5(TransactionKey + Timestamp + MerchantKey + InvoiceNumber +
Reference + Currency + Amount + Result + Modus + SecretKey)

Can anyone give directions on how to get this done?