Google maps (V3) - Map container selector (using jquery)

I'm trying to solve a tricky problem in Google Maps (api V3)

Works nicely:

var map = new google.maps.Map(document.getElementById("map_container"), myOptions);

Doesn't Work if I try to use a jQuery selector

var map = new google.maps.Map($('#map_container'), myOptions);

I made this EXAMPLE

Thank you in advance

Cheers

Pedro