Hi, If you are still looking for an answer, I use the LP5DSM for my CX3, on my Phoenix Ver.2.
When I purchased the sim I asked for the spektrum cable, the dongle cable has a plug on the end that plugs directly into the back of the LP5DSM TX.
When you install the program, Go to System then choose Set Up New Transmitter then when you get to the Select Transmitter Type open the Other option, this has the EFlite Blade CX2 transmitter in the list. It works the same as my LP5DSM.
I hope that helps.