Modest Maps and ArcGIS

I've been looking into hooking the Modest maps Flex client to ArcGIS. Just finished a basic demo for United maps.

I edited a dataprovider.as posted on the modest maps discussion board. Here is the code:

package com.modestmaps.mapproviders
{
import com.modestmaps.core.Coordinate;
import com.modestmaps.mapproviders.AbstractMapProvider;
import com.modestmaps.mapproviders.IMapProvider;
import com.modestmaps.geo.LinearProjection;
import com.modestmaps.geo.Transformation;

public class EsriMapProvider extends AbstractMapProvider implements IMapProvider
{
public function EsriMapProvider(minZoom:int=MIN_ZOOM, maxZoom:int=MAX_ZOOM)
{
super(minZoom, Math.min(20, maxZoom));

var t:Transformation = new Transformation(0.3183098861837907, 0, 1, 0, -0.3183098861837907, 0.5);
__projection = new LinearProjection(0, t);

}

override public function sourceCoordinate(coord:Coordinate):Coordinate
{
var tilesWide:int = Math.pow(2, coord.zoom+1);

var wrappedColumn:Number = coord.column % tilesWide;

while (wrappedColumn < 0)
{
wrappedColumn += tilesWide;
}

return new Coordinate(coord.row, wrappedColumn, coord.zoom);
}

public function toString():String
{
return "ESRI";
}

public function getTileUrls(coord:Coordinate):Array
{
//return [ "http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer/tile/" + getZoomString(sourceCoordinate(coord)) ];
return [ "http://..../ArcGIS/rest/services/MUC_Basemap/MapServer/tile/" + getZoomString(sourceCoordinate(coord)) ];
//return [ "http://..../umapserver/mapdijits/config/proxy.ashx?http://..../ArcGIS/rest/services/MUC_Basemap/MapServer/tile/" + getZoomString(sourceCoordinate(coord)) ];
}

protected function getZoomString( coord : Coordinate ) : String
{
var sourceCoord:Coordinate = sourceCoordinate(coord)
return (sourceCoord.zoom) + "/" + (sourceCoord.row) + "/" +(sourceCoord.column) ;
}

}
}