The clutch on this vehicle is a pull-type clutch, which operates a bit differently from traditional clutches. On a traditional clutch, you would simply unbolt the transmission, pull it out, then remove the pressure plate and replace the clutch disc.
On this model, because the clutch is pulled to release instead of pushed on, you can not simply pull the transmission off, as it is attached to the clutch. Most people run into this issue like you have and attempt to disassemble the flywheel, which while not impossible, is quite difficult and will not get you any farther ahead anyway.
What you need to do is release the collar that holds the release bearing on the transmission to the flexplate on the flywheel. Once this collar is released, the transmission will be free to remove from the engine, and you can then go in and unbolt the pressure plate and replace the clutch disc. Note that the collar is easily damaged; if lots of prying went on leading up to this, you may need to replace the pressure plate if the collar is distorted.
To release the collar, go underneath the vehicle and locate the round rubber plug just below the slave cylinder area on the front of the transmission. Remove the plug and look up into the hole with a flash light. You will see a thin metal collar right where the release bearing contacts the pressure plate. You will need to slide a broad flat head screwdriver in between the release bearing and the collar and perform a twisting motion on the screwdriver to release the collar. If it is stubborn, you can pull the fork toward the driver side of the vehicle to help it along. When the collar releases, the fork will spring out of position and inch or so, indicating it is released.
Once the collar is released, you can go about normal procedure for clutch replacement. On reassembly be careful that the transmission goes in nice and straight; if you go in at an angle and force it again you could damage the collar.
I am attaching some documentation from Mitsubishi to help illustrate it further.