[OT] How to get Install Text in MacOS X .dmg files

[Dave]

Hi,

I'd like to create a new backdrop that says something like "Please  
drag the XXX to the Applications Folder to Install" when my .dmg file  
is opened by the user. Does anyone know how to do this? I've setup a  
Picture and made this the Window Picture in the View Options dialog,  
however, when I open the .dmg file the image is not there.

Thanks a lot, All the Best
Dave