Remote debugging craftbukkit itself?

I want to study the internal workings of craftbukkit. Therefore i want to set breakpoints in the code. But the debugger is not breaking at the breakpoints. This is what i have done.

1. I have downloaded the latest bukkit and craftbukkit into my eclipse using the m2eclipse plugin with the git extension.
2. Im able to maven build and run craftbukkit using the sources of these 2 projects.
3. I have set the startupline for remote debugging: java -Xdebug -Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=y -jar C:\minecraft\development\testserver\*.jar
4. I can succesfully debug plugins using these settings, but on the same run the debugger wont stop at breakpoints in the craftbukkit itself. (I even placed a breakpoint at the first line of the main method but it wont break.
5. I tried many different source folder settings including setting it to the folder where the craftbukkit main class is located net.minecraft.server.MinecraftServer

So my question is how to remote debug craftbukkit itself?
How to make the debugger stop at the breakpoints inside the craftbukkit code?