The 1050's surround back channel processing is a proprietary software from Zoran that works with Dolby Digital 5.1 soundtracks but not DTS (due to the greater processing requirements of decoding DTS, I believe). For this reason, the 1050 will only decode DTS-ES tracks as DTS 5.1. Sorry.

As a somewhat unrelated aside, the Zoran processing (6.1 Surround) can be enabled with 5.1 analog sources to yield 6.1 surround. This method can be used to achieve 6.1 from DTS soundtracks (or Dolby Digital 5.1, DVD-Audio, or SACD, for that matter) decoded by a DVD player's internal decoder and passed via analog connections to the 1050.