Comment 2 for bug 670608

> - This seems like a good idea if there is time. There should be a property
> in HomeButtonApplication (like "program" or "exe") to directly specify the
> executable as it may not always be appropriate to specify the key in gconf.
> So if program/exec is specificed use it, otherwise look up exe from the key.

This is already implemented: HomeButtonApplication has a 'desktopFile' property: if it is set to a valid desktop file, and if the 'key' property is not set, then this desktop file will be used.