the DVD-Video spec only allows for 48 and 96 kHz. Audio-DVD-Creator uses the DVD-Video spec.
to burn 44.1kHz, you need to burn to a DVD-Audio disc. For this, you can use discwelder, WaveLab 5, and a couple others that burn DVD-Audio discs, not DVD-Video.
You also need to be sure that your DVD player can play DVD-Audio discs.