Okay, I might've found a solution, or at least something that works.
A friend asked me why I didn't use ComicRack for viewing comics, which is PC-based. When he showed me how it worked, I noticed an 'export books'-option, which has the capability to export to PDF (and DjVu, but that resulted in a factor 10 size increase). While it is awefully slow to convert, and has a tendency to create pages just a bit larger than the screen of the Pocketbook, resulting in a lot of scrolling, it does work.
Simply said, I connected the Pocketbook, selected a set of comics (Berserk), and asked it to export the books with a custom profile, which is set to put the converted files directly on the Pocketbook (H:, in my case). After about an hour I was able to enjoy Berserk on my Pocketbook.
If anyone knows of an alternative, though, that'd be much appreciated.