DND 3.5 Rend with Extra damage

[Elemist13]

I currently have a player that is a totemist. He currently uses the girallon's blessing spell (spell compendium version) to acquire rend and has the heart of fire soulmeld bond so he gets additional fire damage on his natural attacks. My question is would the additional fire damage also apply to his rend?

[Darrin]

I currently have a player that is a totemist. He currently uses the girallon's blessing spell (spell compendium version) to acquire rend and has the heart of fire soulmeld bond so he gets additional fire damage on his natural attacks. My question is would the additional fire damage also apply to his rend?

I'm inclined to say no. "Rend" is not a natural weapon. It looks more like extra damage to me, rather than a distinct weapon by itself. You can't hit something with just your "rend", it has to be triggered by some other combination of attacks.