Not disagreeing with you exactly, but I spent a bit of time and got my Revo set up just peachy with Just Cause 2. Enter, escape, evade, hand brake, fire1, fire2, zoom all bound fine.
How was this bit of time spent? Did this work out of the box, or did you work around it?
Trying to bind Mouse 4 and 5 just makes it "N/A". It appears to be binding something. As for Enter, it just selects/deselects the option now.
Steam version, Win 7 64, Razer Mamba, Logitech Illuminated.