Well, my old Canon broke down - the lens was not extending and I was getting an error while trying to take a picture. So, instead of throwing it out, I disassembled it and took the lens optics out:

http://avtanski.net/images/microscope/canon1.jpg

What is left inside is small lens that is one unit with the shutter - I did not take this out, because this would mean discarding the shutter itself, and without shutter it just doesn't work well.

The remainder of the camera is now scotch-taped to the microscope (sorry about the bad image - it is quite dark here right now):

http://avtanski.net/images/microscope/canon2.jpg

With the broken lens motor also removed, I can now power up the camera and rotate it by hand - this extends the lens holder and the camera's electronics thinks that everything is well and that the motor works. So, I don't get any errors and the camera works without [most of] the optics.