Change Map Icon

I have found a solution:

In the file "meta-box\js\map-frontend.js" i added folowing code at the Line 56:

// Set marker icon
if ( options.marker_icon )
{
    marker.setIcon( options.marker_icon );
}

Now in the frontend file, i have the new parameter "marker_icon":

$args = array('type' => 'map', 'marker_icon' => 'images/map-marker.png',);
$location = rwmb_meta('my_map', $args);