Hello, WolfgangKurz.
I do not quite understand the question.
If you want to know what settings you must specify in the scanner UI, you need to refer to the user guide (eg. http://esupport.epson-europe.com/ViewArticle.aspx?lng=en-GB&kbid=312750&data=+ab4PwTTw7eByD+QeVbuSTYIGj+oybfB or https://files.support.epson.com/pdf/per12p/per12pu8.pdf).
If you want know what a capabilities enable a one or other mode (without scanner UI), then you need to refer to the TWAIN Specification.
In addition, I have not found a capabilities to work with a TPU, perhaps the scanner driver supports a custom capabilities, but to see it you must contact the manufacturer of the scanner.
I do not quite understand the question.
If you want to know what settings you must specify in the scanner UI, you need to refer to the user guide (eg. http://esupport.epson-europe.com/ViewArticle.aspx?lng=en-GB&kbid=312750&data=+ab4PwTTw7eByD+QeVbuSTYIGj+oybfB or https://files.support.epson.com/pdf/per12p/per12pu8.pdf).
If you want know what a capabilities enable a one or other mode (without scanner UI), then you need to refer to the TWAIN Specification.
In addition, I have not found a capabilities to work with a TPU, perhaps the scanner driver supports a custom capabilities, but to see it you must contact the manufacturer of the scanner.