Well, it's not "enviromental mapping", but is it not the same type of shader? - just instead you're applying a rendered view rather than a cube map. Like I said, if that being the case - You can do it in HLSL with ps1.1 and in just plain FFP (though like I said, ffp envbumpmap has compatability issues on nvidia cards). If I have some time, I'll try and fiddle with it.