How to use custom icons? (Re: Update buddy status from SIMPLE protocol)

[Antonio Gallo]

I was able to patch SIMPLE and make it work i added:
- respond 200 OK to OPTIONS to make Asterisk happy
- respond 200 OK to NOTIFY to make Asterisk happy
- handle Ringing and Busy status inside Notify

What i want to add now is:
1) custom icon for Ringing and Busy status; how can i add custom icon to 
my custom status?
2) notify of voicemail messages ; how can i make appear that you have 
custom emails?

I could not find any devel doc about this.

Antonio