is it possible to replace a vob?

[stretchweider]

hello,
i've been given a promotional dvd advertising a bar thats been created with dvd.stu.pro2.
the dvd contains a promo video of the bar and 2 slideshows.
the bar owner is'nt happy with one of the slideshows and wants to replace it with a new 1.
is it possible to replace the slideshow vob with a new 1 and if so how?
i tried copying the video_ts to my hard drive,creating a new slideshow from iphoto,exporting as dv pal and then using ffmpegx to give me a new vob,i then renamed this vob the same as the old one and replaced it.
i opened the video_ts with apple dvd and selected the slideshow from the menu,the new slideshow plays for approx 15 seconds before im told that the disc is scratched or dirty,even though im playing from a video_ts.
also the new slideshow has no sound.
hope this is'nt too vague but if so let me know and i can give specifics.
thanks

[WiseWeasel]

No, you can't just replace a VOB on a DVD and have it still work. You need to demux the other content on the DVD, and build a new DVD using DVD Studio Pro.

[stretchweider]

back to the drawing board then,
cheers anyway