Does the totemist's natural weapons from Soulmelds behave as if the totemist is large sized if the totemist has Powerful Build?
I've been told that the damage from soulmelds natural weapons cared about the soulmelder's size.
Powerful build only affects weapons held. It says he can wield weapons one size larger without penalty (normally -4 penalty to hit and you can't wield a large 2 handed weapon, but they can with Powerful build at no penalty).
It never affects natural weapons. You don't wield those (since they are part of body).