I doubt such an example exists, if it does it probably doesn't use the same mouse you have.
So use your noggin, you can do it!
I would use an opto isolator, (4N35 or similar) start by lighting the LED inside it up permanently, so the photo transistor conducts, and then wire the photo-transistor across the button. Probably the polarity is important, (the positive voltage side over the switch should be wired to the collector of the photo transistor, but as you have a 50% chance you wire the collector to the "hot wire" of the button, and the emitter to the GND of the mouse. If connecting the photo-transistor doesn't generate a click, simply reverse the two wires. I'm guessing the mouse uses a switch that connects a mouse-logic input to GND, as that's the most logical way to wire up the switch (see figure below for an example).