I'm trying, first - I select the keys tab, click "keybindings depend on orientation" + Select Orientation "90 degress counterclockwise". Then I pressed the key and voila! - you were right, the code appears (). But, when I go to the pull-down list of option - the code dissappears and I can't set anything.
Note that does not happen if I try to set other keys - and FBReader fails ans stops responding. Perhaps the "Quick Launcher" blue button is some type of special firmware key?
I'll try some more - it is a good idea because that's the only key on the tablet rim.