It is possible to add DVD_ROM/JACKET_P/CONTENT folders with PGCEdit... where you have your AUDIO_TS and VIDEO_TS folders, just add DVD_ROM folder or JACKET_P folder or even CONTENT folder... when you follow that guide I posted it will ask you if you want to include them in the making of the .ISO file...... it is that simple... try it out yourself..... easy peasy.....
MY_MOVIE
|
-AUDIO_TS
-VIDEO_TS
-DVD_ROM
*
*
**PGC-Magic**
*
*
MY_MOVIE.ISO