The most straightforward option would be to use Encore's option to add "DVD-ROM" content (on the Disc tab) and include the forms and info on the DVD. In the DVD-Video part of the disc you could add a title screen informing the user that there are extras on the DVD and where to find them.
If you want to be able to link to that extra content from a menu, you would have to use
Sonic eDVD3 which works as a kind of add-on to Encore. Also see the
DV.com eDVD review and Alex Alexzander's
review of eDVD3.
