Some time ago I used the regular method of loading Google Maps API like this:
It's undocumented, but it works.
google.load("maps", "3", {other_params:'key=YOUR_API_KEY', callback: function(){
var map; // initialize your map in here
}});
[EDIT] The documentation now requires the use of an API key that is passed to the loader as a "key" parameter. I've removed 'sensor=false' as a parameter because it is now explicitly not required and throws a warning when provided.