Thanks!
So I have to do it in 2 steps: 1. import with the variables {folder} and 2. replace the character with "Find and Replace". Thats why I put it in the new feature discussion, because it would be great to have it in one step with a special function to the variables, like the Variable Substring Extraction.
Anyway it´s great to get such fast respond to my questions and I always recommend PM to my collegs.