You haven't been looking carefully enough. There
are a bunch of CCFs in the file section that will
work with that model DSS receiver - including
one with the specific model name under the appropriately
named "Dish Network" section of the "Pronto" file
area.

There should also be no problem learning the original
remote with a TSU1000 as a last resort - but as
I said there is no shortage of codes/files for
this player.

The 301 will work with the same codes as the 501,
508, 510, 511, 522, 701, 921, 6000, 2700, etc...

Bruno