I used another version of ultraISO but it didn't resolve the issue.
Yes, I do everything in UltraIso itself, where I add the files in the dirs as discribed.
To resume: I use DVD decrypter to read the ISO image that I burned without speed cams to my harddisk(this DVD works fine on my X5). (This process takes some time(more then an hour..??)) Then I use UltraIso to open the NAV_DB.ISO image. I get the directories DB and TPD, ... and then I add/replace the few files in UltraISO. When I want to burn the image I always see the image is slightly to big.
What settings are you using in UltraIso as properties (optimize?, UDF, Joliet, extendend? I use the settings as described on http://www.bmwnavaddpoi.co.uk/default.htm

Thanks