Icons in the iconbox

[Timothy Hume]

Hi,

I am running Xfce4.05, and am using the icon box rather than the task bar. 
Some of my applications have their own icons (for example, ghostview has a 
little icon which looks like a ghost). However, many of my applications 
(dillo, rxvt, mozilla firefox etc) use a generic icon. This makes it hard 
to see which applications I have running, especially if their windows have 
been minimised.

I read in the FAQ that it is not possible to change the icons in the 
icon box ... this is something the application is responsible for. This 
surprised me, since other window managers (even twm) allow the user to 
specify which icons are used for each application. Does anyone know how to 
trick Xfce into using a particular icon?

Thanks for any help,

Tim Hume