THe OP is mixing up DME with RAC. DME has nothing to do with any airline or any particular resort. If you have a reservation at any Disney-owned resort in WDW, you can take DME. Put the yellow tags on your luggage and they will get it before it hits the luggage carousel and deliver it to your resort for free and you ride the bus for free to and from the airport. On the way back, however, you need to load it onto the bus UNLESS:
Your airline participates in RAC (Resort Airline Check-in). For this, if your airline is listed and it sounds like yours is not, you can leave your luggage at the desk at the resort and they will send it to the airport. Then, three hours before your flight, the DME bus will come to pick you up to take you and your carry-ons to the airport for free.
I hope this helps,
Sharon