Dear Ivan,
thank you very much for your help!
It's not exactly what i searched for, but i goes in the right direction. I haven't recognized the DataExtractWidget yet, but it's really good!
I rebuilded and edited the GP-Service (Data Extract Task) on my own Server and included it in my WebGIS. It's working with my predefined parameters and configuration 🙂
After that, i tried out how to save the Shapefile locally on the server instead of zipping (and downloading) it. I recognised quickly that it is not possible just to edit the "Data Extract Task" of the Server-Toolbox. Later, i checked the python code and found the lines where he zip's the whole folder and saves it. But my python & programming knowledge is not good enough to change this code to saving the shapefile (and shx, dbf, ..) in another folder (if necessary). Because my idea was to save this path and give it to the other GP-Service then ...