Firstly, I would suggest using ent_getskin(mirrorent,1) rather than bmap_for_entity.
I have had far more success using it, its just far more reliable.

Secondly, if it is working on a sprite for you, why not use it into an
ent_decal? Paste the decal onto your entity, an it would work the same I believe.

Thirdly, if ent_decal dont work, or is un-do-able, I BELIEVE you will need two skins
on your model.
Skin1 is the models general texture, and skin2 a 128x128 texture mapped
entirely onto the 'reflective' portion of the model.
Oh, and use 'bmap=ent_getskin(mirrorent,2)' in the view.

See if that can get you started. It will take a bit of tweaking to get it
looking right I believe.
But what Ive given you should get at least some of the view mapped into the model.