Hey. Look at page 51.
Just kidding. Well, kind of. Regarding using the remote control to use the tuner, page 51 of the manual begins the instructions on using the remote, and page 53 discusses operation of the tuner functions. Make sure that you are in the "AMP" mode to use the tuner functions.
As for getting AM stations, page 44 discusses operation of the tuner - which I'm sure that you've read over and over again. I'd try this: select the TUNER as the source, press the BAND button to switch from FM to AM as required, then press the up or down arrow buttons to select a station. In other words, don't press the MODE button. See if that works for you.
I'd sure like to hear the outcome of this. Thanks!
EDIT: BTW, do you have an AM antenna hooked up to the receiver?