There are several ways to do this.
1.downscale in the camera to dv and edit in dv and burn to dvd.
2.capture in hdv, edit in hdv and downscale to dvd-mpeg2 and burn to dvd with Encore.
3.capture in hdv, edit in hdv and export to BluRay and burn to a BluRay disk (need to author it first in Encore)
When you want HD quality on DVD you need a BluRay player to view the content: export to Bluray mpeg or H.264 and authore it to a BluRay iso in Encore. Burn with Nero onto a DVD. Single layer will hold about 20 minutes of HDV timeline.