Neither RX will work. The 4 CH WK 2401 will not allow you to set-up the swash-plate or other parameters for this type of heli. Not sure the 2401 will even work with a RX2801 or RX2701, even with the first 4 channels: ELE, AIL, THR, RUD. Rick at Clubheli.com is "blowing-out" some extra WK-2801's and WK 2801-E's at $139. I got a an E model for this price, a good deal.

Walkera has also just announced the WK2801PRO, which has the ability to switch between 10mA and 100mA output. You can download the manual at their web-site. Given Walkera's penchant for rapidly changing their specs, even within models without announcement, I am currently reviewing the new manual to see what new "goodies" they have stuffed-in the PRO.