Navigation in a newspaper is painful

I read the "Sueddeutsche Zeitung" with adobe digital editions.

The navigation is very very painful:

* Using mouse wheel -> slow scroll, unusable

* Using key down -> slow scroll, unusable

* Using page down -> jumps a complete page, so far so god. But with Zoom >1 the key page down should not jump a complete page, but just to the next viewable page section

* CTRL + MouseWheel does not zoom