[Plugin: Comprehensive Google Map Plugin] Open Street map extra layer mod?

Hi I am kind of keen to use this layer on open streetmap
http://maps.stamen.com/#watercolor/9/51.4894/-2.2358

I looked through your code for “layer” looking fro where I could add this:

/ replace “toner” here with “terrain” or “watercolor”
var layer = new OpenLayers.Layer.Stamen(“toner”);
var map = new OpenLayers.Map(“element_id”);
map.addLayer(layer);

But couldn’t see It. Is this going to be possible do you reckon?

http://ww.wp.xz.cn/extend/plugins/comprehensive-google-map-plugin/