PAL and NTSC standards are different so the video would have to be encoded from one format to the other with an MPEG encoder. I used TMPGEnc for this but that was a long time ago.
The only other option I know of is editing the IFO file to try to fool the DVD player into thinking the video is the other format but most DVD players will still reject the video since it is really the other format which the player was not designed to play.
AnyDVD does not claim to be an MPEG encoder so you should not blame SlySoft.
Search "convert PAL to NTSC". AfterDawn has a good guide for this showing different methods.