ActionScript 3 :: Flash - Expose A Vector As An Enumerable Type?

I have a class member in an ActionScript 3 class that looks something like this:

private var m_myvect :Vector.<MyType> = new <MyType>[];

I'm exposing it through a getter, like this:

public function get mydata() :Vector.<MyType>

Which doesn't help when I use it like this:

for (var o:Object in inst.mydata)
{
...
}

... because the type of o is not MyType, but Number instead, because it enumerates the vector indices instead of the data.How would I expose only the data within the vector in a way which:Does not expose the data in a way which allows it to be modified?