Hi Marco,
Greeting from Syncfusion.
We can load and view the rotated PDF document in PDF Viewer. But at present we don’t have support to rotate the PDF document in viewing time itself. Could you please confirm us whether this is what you have mentioned as "To add the PDF document in rotation feature" in your update? So that it will be easy for us to investigate further on the requirement and assist you with the better solution.
With Regards,
Gayathri R