I need to update this code:

radar_layer.getTileUrl=function(tile,zoom) {

    var llp = new GPoint(tile.x*256,(tile.y+1)*256);
    var urp = new GPoint((tile.x+1)*256,tile.y*256);
    var ll = G_NORMAL_MAP.getProjection().fromPixelToLatLng(llp,zoom);
    var ur = G_NORMAL_MAP.getProjection().fromPixelToLatLng(urp,zoom);
    var dt = new Date();
    var nowtime = dt.getTime();

    var tileurl = "http://demo.remoteservice.com/cgi-bin/serve.cgi?";
        tileurl+="bbox="+ll.lng()+","+ll.lat()+","+ur.lng()+","+ur.lat();
        tileurl+="&width=256&height=256&reaspect=false&cachetime="+nowtime;

    return tileurl;
};

I got as far as:

var DemoLayer = new google.maps.ImageMapType({

     getTileUrl: function(coord, zoom) {

     var llp = new google.maps.Point(coord.x*256,(coord.y+1)*256);
     var urp = new google.maps.Point((coord.x+1)*256,coord.y*256);
     var ll = googleMap.getProjection().fromPointToLatLng(llp);
     var ur = googleMap.getProjection().fromPointToLatLng(urp);
     var dt = new Date();
     var nowtime = dt.getTime();

     var tileurl = "http://demo.remoteservice.com/cgi-bin/serve.cgi?";
         tileurl+="bbox="+ll.lng()+","+ll.lat()+","+ur.lng()+","+ur.lat();
  tileurl+="&width=256&height=256&reaspect=false&cachetime="+nowtime;

     return tileurl;

     },
             tileSize: new google.maps.Size(256, 256),
             opacity:1.0,
             isPng: true
         });

Specifically, I need help with this section:

var llp = new google.maps.Point(coord.x*256,(coord.y+1)*256);
 var urp = new google.maps.Point((coord.x+1)*256,coord.y*256);
 var ll = googleMap.getProjection().fromPointToLatLng(llp);
 var ur = googleMap.getProjection().fromPointToLatLng(urp);

The service wants the tile bounding box from what I understand. However, ll and ur do not seem to correct at all.

I had it working and displaying the entire map bounding box in each tile, but of course that's not what I need.

Any insight here would be greatly appreciated, not having the GTileLayers in V3 is fine if I can work around it, until then I'm frustrated.