Thank you,
wallcraft!!
I tried what you told me, but Mobipocket creator won't create the HTML file. I am pretty sure yesterday it created them. Now it only creates an OPF file, the PRC file and copies of all jpgs.
I'll try to see what happened, I can't believe that just for checking the jpg option now it won't create the HTML.
About the margins, if it can't be fixed... well! I'll try to read big vignette manga for now and hope for Booken to release that long awaited zip-support update.
Thank you again!!
If anybody has some ideas for all of the above, please post them! And If I work things out by myself, I'll tell you how I did...