Is it possible to export a movie to DVD with dolby surround 5.1 sound or vorbis 5.1 ?

Kdenlive does support 5.1 Audio channels and also display them in Timeline. But the most audio effects are only for stereo, so you can't edit 5.1 Surround properly.
The better Way will be to do the video editing in Kdenlive and then do all the sound in an editor like Qtractor or Ardour. Xjadeo will help you to monitor video while creating the audio.