Creating big DVD ISOs with mkisofs

We’re trying to bundle a lot of stuff on a DVD, and recently ran into the problem that the cab-file InstallShield creates is too big for mkisofs.

The cab-file is just above 4GB large, which I guess means we’re getting close to dual-layer territory.

Does anyone know if mkisofs can create dual-layer ISOs?

If it does, why did it fail on this file that should be small enough to fit fine on a dual-layer DVD?

The harddisk where you create the image is it FAT32 or NTFS.
Because if it’s FAT32 then it will not support files over 4Gig.