hie,i have a moto L7 SLVR,(R4513_G_08.B7.ACR_RB) my phone key pad is not working,the navigation key, red key, and number 9, these three keys r not working, i want to change red button i would be happy, pls tell me how to change the red key to any other one, i don't know how do it, cau u pls help me out.. and if i want to buy it wat would be the cost of the inner key pad...