I was talking to a friend "shaderman".... He explained me what is happing..
The problem is the Tangent value from 3DGS isn't a float4 but a float3 ....

So... this

Code:

---

 
void CreateTangents(float3 inNormal,float3 inTangent)
{
	matTangent[0] = DoPos(inTangent);
	matTangent[1] = DoPos(cross(inTangent,inNormal));	// binormal
	matTangent[2] = DoPos(inNormal);
}

---

Should be something like this

Code:

---

 
void CreateTangents(float3 inNormal,float3 inTangent)
{
	matTangent[0] = DoPos(inTangent);
	matTangent[1] = DoPos(cross(inTangent.xyz,inNormal)) * inTangent.w; //binormal
	matTangent[2] = DoPos(inNormal);
} 

---

Is this possible to correct the previous posted code?
Thanks....