Changing Tax Base

[eknitwear]

Hi

 

What if we want to Add a Tax Rule BASE? like currently prestashop ask if we want to add a tax price based on delivery address etc what if we want to add a tax price based on Payment Option.

 

What i basically mean over here is that we want to add a transaction fee at the time of checkout if customer is using our 2checkout payment option.. so any help in this regard???

[eknitwear]

any help?????