change dmg icon

Hi to all.I am new in Mac-forums.I am developer and this is the first time that i was asked to make a dmg file.I have done it using macdelpoyqt in order to copy the appropriate libraries into the application package.I want to change the dmg icon in order not to use the XCode default icon and not to have any legal problems. The application's icon has changed. The only icon i want to change is the dmg file.Without mounting it. Now it has the hard disk icon. Can i change it somehow?Thanks in advance.