Yup i did, but there seemed to be a bigger problem, i share with you my solution... i had to firt take the materials my mesh already had and save it on a var...

var Suits : Material[];

var Detail : Material[];

var currentSuitIndex : int = 0;

var currentDetailIndex : int = 0;

var currentSuit : Material;

var currentDetail : Material;

var currentSuitMat : Material[];

var ColorSuit : Color[] = [Color.red, Color.white, Color.blue, Color.green, Color.yellow, Color.black, Color.cyan, Color.magenta, Color.gray];

var currentSuitColorIndex : int = 0;

var currentDetailColorIndex : int = 0;

function Start ()

{

currentSuitMat = renderer.materials;

ActivateSuit(0);

ChangeSuitColor(0);

ChangeDetailColor(0);

}

function ActivateSuit(index : int)

{

if (index >= Suits.Length)

{

    index = 0;

}

currentSuitIndex = index;

currentDetailIndex = index;

currentSuit = Suits[currentSuitIndex];

currentDetail = Detail[currentDetailIndex];

currentSuitMat[1] = currentSuit;

currentSuitMat[2] = currentDetail;

renderer.materials = currentSuitMat;

}

function ChangeSuitColor(index : int)

{

if (index >= ColorSuit.Length)

{

    index = 0;

}

currentSuitColorIndex = index;

currentSuitMat[1].SetColor("_Color", ColorSuit[index]);

renderer.materials = currentSuitMat;

}

function ChangeDetailColor(index : int)

{

if (index >= ColorSuit.Length)

{

    index = 0;

}

currentDetailColorIndex = index;

currentSuitMat[2].SetColor("_Color", ColorSuit[index]);

renderer.materials = currentSuitMat;

}

function Update ()

{

if (Input.GetKeyDown ("s"))

{

    ActivateSuit(currentSuitIndex + 1);

} 

else if (Input.GetKeyDown ("d"))

{

    ChangeSuitColor(currentSuitColorIndex + 1);

} 

else if (Input.GetKeyDown ("f"))

{

    ChangeDetailColor(currentDetailColorIndex + 1);

}

}

Yes you find the object within your character that has the material. If there is an array of materials, it will be indexed like any other array of things.