Thanks but my problem is mostly that the script cannot find the sampler called "Mesh" when I add the pkfx via script.
I have it working fine otherwise.
Here is the code which is on the start function :
_effect = this.gameObject.AddComponent<PKFxFX>();
_effect.m_FxName = "Skinned_Effect.pkfx";
_effect.SetSampler(new PKFxManager.Sampler("Mesh", new PKFxManager.SamplerDescShapeSkinnedMesh(Vector3.zero, Vector3.one, Vector3.zero, this.GetComponent<SkinnedMeshRenderer>(), (int)PKFxManager.EMeshChannels.Channel_Position)));
this.gameObject.GetComponent<SkinnedMeshRenderer>().enabled = false;