Right now I'm far away from home, but I've found some extra time to work on my code for APM. But how am I going to test it without APM? Here is the video which shows a successful run of modified APM code on virtual APM =)
"\n" is not working good on this emulator.
Here is what you need:
Arduino IDE direct link
Proteus (I'm using v7.7 sp2) Demo version (according to demo limitations it cannot save or modify any MCU simulations, but you won't need it - you can use mine in read-only way, no problems with changing firmware) UPDATE: Unfortunately, there is no way to run my simulation file unless you have full (paid) version of Proteus.
APM firmware source code v2.24 (use newest if available)
and my Proteus simulation file attached (or you can do you own - it is really simple) ardupilot_sim.rar
UPDATE2: It is also possible to use AVR Simulator from AVR studio with HAPSIM plugin to get it running, but on my netbook it is sooo slow - so I couldn't make the video.
I hope it helps.