<?php
class Test {
    private static $data1 = 1;
    private static $data4 = 4;
}

class Test2 extends Test {
    private static $data2 = 2;
    public static $data3 = 3;
}

$r = new ReflectionClass('Test2');
$m = $r->getStaticProperties();

$m['data1'] = 100;
$m['data2'] = 200;
$m['data3'] = 300;
$m['data4'] = 400;

var_dump($r->getStaticProperties());
?>