Go to the options, disable Joliet and enable ISO9660 level 2 (level 1 is 8.3 format, level 2 is 32 letters upper case). If you find an option to not convert file names to upper case, enable this, too.
Another possibility is to use a file system on the Amiga which can read Joliet CDs like CacheCDFS or AsimCDFS.
Bye,
Thomas
