The coordinate was added to the engine:
V7.05.1b beta - released 6-Aug-2007
So, I am sad to say that you are out of luck with A6.
I don't call createTangents... So I do this to the FX file.
Global declare:
float3x3 matTangent;
Change the vertex input struct:
float4 tangent : TEXCOORD2;
Then this code in the shader:
tbnMatrix[0] = mul(IN.tangent.xyz, matWorld);
tbnMatrix[1] = mul(cross(IN.tangent.xyz, IN.normal), matWorld)* IN.tangent.w;
tbnMatrix[2] = mul(IN.normal, matWorld);
Eric