Thanks for the response.

The problem is that I don't really want to replace some icons.
In the status area I have for instance the IM status that shows a green dot (as you may see on the second picture here) when I am online or when a custom status is online. What I want to do is customize that green dot to be a sip icon when my custom sip status is online and a facebook icon when my custom facebook status is online, same for skype etc.
Now no matter what is my custom status icon (a house, a ball etc) my status area icon is always a green dot when that status is online.
Where can I change that?