I have access to a map server that takes a bounding box measured in degrees, and returns a map, projected in Web Mercator. I'm having trouble configuring OpenLayers to use a Mercator projection that isn't measured in meters. In particular, when I pan the map along the Y axis, the new image is further north (or south) than expected, and the graticule markings become increasingly incorrect.
The layer has sphericalMercator = true and is using a new projection I created with degrees for units and a reasonable maximum extent. I also added my new projection to the list of geographic codes in Projection.js so that it can be converted to 900913. Does anyone have any experience with a map setup like this?