Can anybody give me some clues on getting MPLAB's simulator to work?

Here's my situation: I'm a relative newbie to PIC chips.  I have done
assembly language work with other microprocessors such as the Z-80, 6502
and 6800.  Now I want to start programing PICs in assembly language.  I
have a morse code program written by a third party that is currently
working.  A 12C509 is beeping at my elbow as I type this.  (The code is
at http://www.tfs.net/~petek/morse/morse1.html if you'd like to see it.)

I assembled it with Mpasmwin.exe, which came with MPLAB 3.400, used the
hex file it generated to program a 12c509 chip with the EPIC programemr
from Microengineering Labs and it runs fine.  I've made a few
modifications and they run fine too.

Now I'd like to make some major changes to the code and I'd prefer to
test the code using MPLAB's simulator instead of editing, assembling,
burning, testing, editing, etc.

But for the life of me, I can't figure out how to get MPLAB's software
simulator to work.  I've gotten to the point of creating a project,
running Project/Make and getting a clean compile, except for a couple of
warnings about things I specified, such as HEX, being overridden by
command line parameters (also HEX, so no problem.)  Clicking on one of
those lines of error messages takes me to the appropriate line in the
.ASM file.  Feeding the hex file to a programmer makes a working chip.
So obviously a lot of things are working right.

But nothing I do seems to get the simulator to start.  Debug/Run and
Debug/Execute both have all their options greyed out.  Clicking on the
Green stoplight gives me a click and nothing else.  Ditto for the foot
marks.  Clicking on ROM shows me the program memory, clicking on RAM and
SFR does nothing..

As for reading the help files, well they certainly seem to be unique set
of documents.  I wonder if Microchip accidently released the
specifications for the help files instead of the actual help files.
They seem to be more descriptions of what information they should have
than the actual information itself.

I'm not sure if MPLAB's simulator actually covers the 12C509, so I
changed the software to specify a 16F84.  Project/Make works all right,
but I haven't got a chip handy to program, so I'm not sure it works.
But I know that I can't get MPLAB's simulator to work with this
configuration either.

Can anybody give me some clues to getting this going?  I'm fairly
confident that once I get the simulator simulating something, I can
figure out the rest on my own, but getting past step one has me baffled.

Thanks,
Dave Mullenix, N9LTD
PIC Programmer wannabe