How to debug Glassfish itself

Hi,

I have checked out the GF sources and I'm able to successfully compile the whole glassfish project in netbeans.

My question is, how can I debug the glassfish project in netbeans, so I can watch the startup process, set breakpoints and so on? The "run" and "debug" buttons in netbeans are disabled.

Thanks for your help.

Wasomumba