You need to petition the Yankees...not Dish. They only reason they aren't on Dish, according to many posts, is that the Yankees demand being included in one of the primary packages, (like the AT200), and will not settle for only being in the sports package or a-la-carte like all the other RSNs. They are trying to force ALL subscribers to have to pay for their channel, instead of just the Yanks fans.
While I sympathize with the Yanks fans wanting the channel, as a Mets fan (or any other team) I wouldn't want to be forced to pay for the channel in my regular package!
If you're interested, do a search...there are dozens of posts about this channel floating around.
A Houseful of Samsung TVs - 55" 8500 Series LED LCD | 32" 5500 Series LED LCD | 32" LN32A450 LCD | Dish Network 1000.4/Eastern Arc | 1 Hopper/2 Joey | SilverSensor ZHD-TV1 OTA Antennas