Actionscript 3 :: Pass All Parameters (one By One) In An Object To A Constructor?

I have the Class and the parameters of its contructor as an object. What I need to do is a function that returns an instance of this class, passing this parameters to the constructor.

This is the code:
Some random and unmodifiable class:

public Foo {
public function Foo(a:int, b:String) {
// constructor
}
}

And some function (in some another class):

function bar(params:Object):* {
var baz:Foo = new Foo(params.a, params.b);
return baz;
}

What I need to do is make this function generic, without pass params as parameter to Foo constructor because I can't modify it. Something like:

function bar2(clazz:Class, params:Object):* {
var baz:* = new clazz(/*some magic way to transform params in comma separated parameters*/);
return baz;
}