Only certain video files getting Published to Roamio

Context: I want to watch video files on my Roamio.

So, using Tivo Desktop (paid version), I have specified a folder on my Win7 64 PC hard drive to share videos with my Roamio.

If I go to
http://www.hd-trailers.net/
and choose a film, follow the links and save a trailer, I get an .mp4 file that I copy into my published folder. This is what the file specs are:
Image may be NSFW.
Clik here to view.

Within a minute or two, this file is available on my Roamio, I can play it, it works great.

With me so far? Ok, now if I go to
http://www.demo-world.eu/2d-demo-trailers-hd/
and choose a Dolby 5.1 trailer and download an .m2ts file, here's what I see:
Image may be NSFW.
Clik here to view.

Since I know Tivo doesn't support .m2ts, I then use kmttg to convert the .m2ts file using these default settings:
Image may be NSFW.
Clik here to view.

Then, I copy the resulting .mp4 file into my published folder. For reference, this is what the converted file shows:
Image may be NSFW.
Clik here to view.

However, and here's the problem: this converted file never appears on my Roamio. It's as if Tivo Server and my Roamio just ignore it. So, the question is, why?

Any guidance here greatly appreciated.

Thanks

--jay