Set scale information for a specific key frame in the animation set.
HRESULT SetScaleKey( UINT Animation, UINT Key, LPD3DXKEY_VECTOR3 pScaleKeys );
If the method succeeds, the return value is S_OK. If the method fails, the following value will be returned: D3DERR_INVALIDCALL.
Header: Declared in D3dx9anim.h.