VOB to ISO?

[Eidolon]

First I want to compliment Lightning on a great program. Second, there is small issue I'm having. I rip the DVD using file mode. I then use IFOedit make any changes I need and change the vobs/ifos. I now need to burn the files onto a DVD-R. I could use Nero to just dump the files directly onto the DVD but I'm having compatibilty troubles with my burner (Sony DRU-500A) and Nero.

My question is fairly simple: Is there a way I can convert the vobs and ifos into an image file? I'm guessing that would either be a .dvd or .iso file. If I can make an image I can burn it using DVD Decryter or some other program (right now I think I'm limited to Nero since I don't know how to make the images). I might just be confused about something, so let me know... :)

I read something about prassi earlier. Do you have a link? Is it freeware? Is that the best tool to use?

[LIGHTNING UK!]

Prassi isnt freeware. IFOEdit has a util called imgtool or something like that which can build iso files from the vobs and stuff I think. You access it via the 'Disc Image' button.
Test the ISO using DAEMON Tools before you commit yourself and go burning it to a dvdr with DVD Decrypter or whatever.