Well, after getting through to the new tech support person  (who is working on getting the instructions together, and obviously has her hands full) I decided to give it a try.  I learned quite a bit in the process, that I thought I'd pass on to anyone who wants to refill their toner cartridge.

1) Do it in the basement, if possible.  If not, the laundry room sink.  Clean off EVERYthing around the sink.  Cover the inside of the dry sink about 10 layers of newspaper, and cover a working surface next to the sink, as well. Wear a dusk mask, if you have one.  Wear work clothes that can get dirty.  (P.S. I am usually more capable than most with this kind of messy work, but the toner dust can easily get around, and an "empty" cartridge still has LOTS of toner in it, that needs to be emptied. 

2) Before you cut the hole with the iron, I suggest looking carefully at your toner cartridge, to see if there are slots or openings near where you are going to be making the hole.  I would suggest getting some clear wide plastic or masking tape (not duct tape - the glue sticks) and taping a plastic cover over these holes (if you can see that you won't be taping directly to anything but the outside of the plastic cartridge).  This way - the ink that you empty out, won't fly back in, as it hits the newspaper and soil the inside of the cartridge slots - (which I'm sure should stay as clean as possible) as it did with mine. :(    Then, of course, take this plastic off, when you are done the refill process.

3) Put the cartridge in the dry sink.  Put the iron on the stand and heat for 3 full minutes, as recommended.  Hold the cartridge at 90 degrees, so the surface that you will be making a hole in, is perpendicular to the bottom of the sink.  This way, the plastic hole you punch will not have the full weight of gravity pulling on it.  DO NOT hold the cartridridge upside down, thinking that this will stop the plastic part from falling in (as I did) - unless you want tons of toner to fall out immediately, in all directions, below the hole.  MESSY!! (I'm lucky I didn't end up looking like the mad scientist)  :)

4) When you put the iron to the plastic, turn slightly as you put pressure on it.  Don't push too hard. Easy does it.  As you turn, the heat of the iron and the turning action cuts easily through, with a slight stead pressure.  You don't want to push the iron into the drum, as it cluts through.  (Somehow I think I managed to avoid doing this, in my first hole punching! :)  )

5) Emptying the Old Cartridge - This is required, or the new toner won't be fresh, etc. I'll call this "Cleaning the Chimney", because that is the closest thing most of us will ever come to handling this level of sooty black stuff.  If you have a few open sheets of newspaper in the sink, and the slots of the cartridge covered - you should be fine.  Once you get a pile of toner emptied onto the newspaper, carefully put the cartridge down somewhere, and fold the newspaper up in a careful way and place in a plastic bay.  Do this as many times as necessary.

6) Refill your old empty cartridge. Tap on the bottle to free up the toner, before you start.  My cartridge was able to take the full amount of my refill kit, but they say, if it gets full - stop. 

7) The plastic plug only pushes down about half way, to make a tight seal.  I was warned not to push too far in - or things could get damaged.

8) Take all newspaper out of the sink. Clean the cartridge of any toner ink that got on it with a dry painter's brush.  The toner washes right out of the brush with water.  Dry off the brush really well, with a towel.  Repeat until the brush stays clean.

I still haven't put my cartridge back in, but I'll let you know how things go.

Hope this helps!  Wendy