At this point your options are really only limited to Sonic's EDVD to link any amount of on disk content. With encore you can put the presentations on the disk but you are unable to link them to the DVD menus.
Quite easily. Under the Disc tab there is a DVD-ROM Content area. Hit browse and navigate to the folder that has the data.
We have had good luck with this using a Macromedia Director File tat launches when DVD is placed in a PC. The viewer can still access the DVD video by right clicking and choosing Play with (DVD Player) and of course when inserted into a set top DVD player DVD video takes over.