As I could not recall it :

Loaded a HDV 1440x108i with native MP2 stereo audio, and then Create DVD 16x9 rendering does transcode the audio to AC3 by default.
Video is displayed with correct aspect ratio using VLC and .

Input #0, mpeg, from 'dvd.mpg':
  Duration: 00:06:58.08, start: 0.160000, bitrate: 8269 kb/s
  Stream #0:0[0x1bf]: Data: dvd_nav_packet
  Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, bt470bg, top first), 720x576 [SAR 64:45 DAR 16:9], 25 fps, 25 tbr, 90k tbn
    Side data:
      cpb: bitrate max/min/avg: 8000000/0/0 buffer size: 1835008 vbv_delay: N/A
  Stream #0:2[0x80]: Audio: ac3, 48000 Hz, stereo, fltp, 224 kb/s

Is it possible to get MP2 audio; if possible how and where to set it on the create DVD or Batch render window?
I tried to check FFmpeg there, but could not see MP2.