Ornithopter

I've just recently set up SRS, and the only thing that I cannot get working are the presets. I've put a text file in the Simple Radio root directory (in this case, called 'r828.txt' and filled it with a couple of frequencies for use with the Su-25. I've tried other radios, on other airplanes as well. However, I've not been able to get SRS to read these files to populate the presets. What could I be doing wrong?