Actions inside MC's

Hello,

I have a ‘menu bar’, and inside that MC are my navigational buttons (MC’s).

When the mouse hovers over the relevant button, I wish it to change colour. But NOT the whole bar including all of the buttons which mine is doing!

It is stacked accordingly: menu_mc.bio_mc etc for each button.
menu_mc being the navigation MC
bio_mc being a button inside it. (aswell as calander_mc, contact_mc etc etc)

this is my code: (ps. I am using a lacos class ‘colorTo’)
For some reason, all of my buttons goto white on Rollover… why is it not working? I though I have made a clear path to what should be activated.
//
function menuover (){
this.colorTo(0xffffff , 1);
}

function menuoff (){
this.colorTo(0x999999 , 1);
}

menu_mc.bio_mc.onRollOver = function(){
menuover();
}
menu_mc.bio_mc.onRollOut = function(){
menuoff();
}

//

Thanks >>>