My Harmony 880 does not control my H21-700

After a bit of playing I am 100% certain that my remote is in
RF mode and this is the issue. I cannot find any settings whatsoever to
change the H21-700 to IR. Any ideas ????

Go into menu of the receiver:

1. menu: parental,fav's & setup> system setup> remote> IR/RF>

2. you will see either IR or RF, click whichever to reveal both

3. chose IR, the remote will stop controlling the receiver, do the following on the remote:

a) dtv
b) press and hold MUTE & SELECT for two blinks
c) enter 0 0 0 0 1

4. press dONE and exit the menu