Sending class name to another class

I have a movieclip in a library with a class name: menuItemMC

now I want to send this to another class:

var myClass:CustomClass = new CustomClass(menuItemMC);

and then in that class I need to use this like:

public function CustomClass (menuItem:* );

var customID:**menuItem;
customID = new ****menuItem();
I tried something like this, but its not working…how do I receive this and use it from there?