Logitech's software is crap nowadays. Setpoint is huge, and last time I looked, it wasn't updated for two years at least. It makes keys stick when you program keyboard shortcuts onto the mouse, such as ALT-F4.
If you are inclined to do a bit of dirty work and are somewhat knowledgable with computers and scripting, you could look into AutoHotkey. I've programmed my mouse by catching the mouse button input and then having AutoHotkey 'press a key.' After compiling the script to an EXE (assigning a nice icon to it), I now have a fully programmed mouse. The "program" is something like 1 MB in size, and takes 2.1 MB RAM. (As my mouse only has a wheel tilting left and right as button 4 and 5, the AHK script only has two lines in it
)