Я нашел решение ...
CLLocationCoordinate2D lcA = CLLocationCoordinate2DMake(oSector.f_overlay_lat_min,oSector.f_overlay_long_min);
CLLocationCoordinate2D lcB = CLLocationCoordinate2DMake(oSector.f_overlay_lat_max,oSector.f_overlay_long_max);
CGPoint cgA = [mvMap latLongToPixel:lcA];
CGPoint cgB = [mvMap latLongToPixel:lcB];
float fLatMin = MIN(cgA.x,cgB.x);
float fLongMin = MIN(cgA.y,cgB.y);
float fWidth = sqrt((cgA.x - cgB.x)*(cgA.x - cgB.x));
float fHeight = sqrt((cgA.y - cgB.y)*(cgA.y - cgB.y));
RMMapLayer *mlLayer = [[RMMapLayer alloc] init];
mlLayer.contents = (id) oSector.im_overlay.CGImage;
mlLayer.frame = CGRectMake(fLatMin,fLongMin,fWidth,fHeight);
[[mvMap.contents overlay] addSublayer:mlLayer];
mvMap - это IBOutlet RMMapView * mvMap где-нибудь в вашем h-файле
oSector.im_overlay.CGImage может быть
UIImage *i = [UIImage imageNamed:<something>];
lmLayer.contents = i.CGImage