andrew,

just because some other devices, even if made by the same mfr. all have the same functions. Also, just because there's a button on the unit, that doesn't mean that the button has a remote access signal. My eq has buttons to enter memory settings, but I can;t mimic those buttons with an Ir signal.
You apparantly use AMP_0013 for the receiver. If you're so convinced there is a "direct" signal, set the rmote in the receiver mode, and press P-E,F,C with efc=000>255. If it exists, you should hit it. If not, then it simply doesn't exist.
Jim