movieMaterial.movieTransparent = !?!

I’ve been messing around with this for a while, I can set the transparency of a movieMaterial (in PV3D) when instantiated(i.e. new MovieMaterial(asset:*, transparent = true); But for the sake of optimizing my FLV, I need to turn the transparency on/off when certain planes are selected. For some reason, when I set movieMaterial.movieTransparent = false/true, the material does not respond. The material is set to animated=true. What am I missing here?