Static constructors inconsistency

[spec via Digitalmars-d-learn]

Hello, i'am experiencing some non consistent behavior with static 
constructors. I wonder if this is some bug or i just don't know 
enough of D (most probably!).. Code example bellow:

//------------------------------------------
module main;

import std.stdio;

class B
{
	static this()
	{
		A a = new A;
		int val = a.getValue("A");
	}
}

class A {
	private static int[string] aa;
	
	static this()
	{
		aa = ["A":1, "B":2];
		writeln("@ A static ctor!");
	}

	int getValue(string str)
	{ 	
		return aa[str];	
	}
}



void main(string[] args)
{
	B B = new B;
}
//------------------------------------------

The text "@ A static ctor!" never gets printed. The inconsistency 
(IMHO) is that if i do any of this:
- Declare class A before B;
- Change the var declared in A from an AA to some other p.e int;
- Comment the line "int val = a.getValue("A")";

Maybe there are some other points, but at this point i got 
confused and decided trying to understand it. Anyway with any of 
those changes the text gets printed.

Anyone able to shed some light into this?

Cheers,