Binding skin weights/joint indices to a profile_CG parameter

I cannot seem to figure out how I bind (as in <instance_material>/<bind>) an effect parameter to a <controller>/<skin>'s weights or joint-indices per vertex data. According to what I have gleaned from the documentation the <skin> and its associated <vertex_weights/<input>'s do not seem to be on the search path for either the <bind>'s target attribute or <bind_vertex_input>'s input_semantic attribute. Can somebody shed some light on this situation?