Imaging multi-session DVDs (non-CSS disk)

On Windows XP a client had a multi-session DVD (non-CSS so non-commercial on a DVD-R) and wanted a copy. Using their PC (a business grade DELL) I had problems with creating an image of this disk using imgburn. Imgburn suggested to create a new layout by hand. I tried that but  ended up with an image that was much smaller (300 MB verses 900 MB) than the original. This got me curious.

I also tried the daemon tools image creation and that could create a .MDS or .MDX file that was the right size but that would not mount in Daemon tools and nor did the daemon tool image burner work on that file.

What I did try was using infrarecorder to create an image. This successfully created a .ISO file that was the right size and could mount this in daemon tools. Infrarecorder could not actually burn this image (it just ejected the disk immediately) but imgburn could.

So the final workflow was,

Infrarecorder -> .ISO -> imgburn

and the client says that the new copy works on their DVD player.