Array of subclasses

[DarkRiDDeR via Digitalmars-d-learn]

Hello. I have a class:

abstract class Addon
{
	public activate(){...}
	...
}

its children:

class A: Addon {... }
class B: Addon {... }

How do I create an array of subclasses Addon? For example, one 
could to do so:

T[2] addons = [new A(), new B()];
foreach(T addon; addons){
	addon.activate();
}