Here you go:

Code:

---

 
material right_alpha_mat
{
  effect =
  "
    technique right_alpha1
    {
      pass p0 {zWriteEnable=true; alphaTestEnable=true;}
    }
  ";
}
 

---

In the action of your character write this:
Code:

---

my.material = right_alpha_mat;

---

That should solve the problem.