Call a private static method from a closure (inside the class) - closures

Question

I am trying to call a private static method of a class from inside a closure inside an other method of this same class, and I can't find the right way to do it...
even using use referencing the private method...I am able to reference a private variable and pass it, but no way to reference the private method...
$refMethod = array('App','_onEvent'); with call_user_func($refMethod) will throw the method is private...
I tried with ReflectionClass with PHP 5.4 version also, (WAMP 32bits), but it says that the getClosure method doesn't exists on the instance :(
class App(){
static public function start(){
new Form('myform', array('submit'=>function($form) use($someVar){
if($anyCondition){
// want to call private self::_onEvent here : any suggestion ?
}
}));
}
static private function _onEvent(){
// this is my very private part
}
}
Well I know quite closure has no scope but so...any way to pass the private context (because the closure is inside the class) for accomplish something like this ? Thanks for any lights !
EDIT : I exactly want to do this answer but this just throw the great
Cannot access self:: when no class scope is active

Answer 1

Ok dudes,
it works better with PHP 5.4, my upgrade was not ok, I finally get rid of boring complications when upgrading php version, and now the straight solution works :
calling directly self::privateMethod() won't throw the 'self is nothing in closure...' anymore
Appart from that, did you know that from now (5.4), (0 == 'anystring') is TRUE now, duh ! need to use strict equal everywhere now, wonderfull upgrate :-s