PHP OO problem

Take the following example class Foo which defines a static method called X that statically calls another of it's method's called Y using self::Y() as follows.

<php> class Foo { public static function X() { self::Y(); } public static function Y() { echo( "This is Foo::Y" ); } } </php>

Now lets say that Foo is part of a core library that we don't have commit access to and we want to make a modified version of the functionality via a sub-class of Foo called Bar which overrides the Y method as follows.

<php> class Bar extends Foo { public static function Y() { echo( "This is Bar::Y" ); } } </php>

The problem

The Y method is only ever called via the self::Y statement in the X method, so when we call Bar::X() it's actually Foo::Y that executes, because X only ever executes within the context of Foo since we haven't overridden the X method with a definition in the Bar class.

The question

Is there a way to define a Bar::X method that calls Foo:X while maintaining the context of Bar (i.e. the value of self is "Bar" during execution of Foo::X?

Notes

It seems to me from the documentation about forward_static_call that the following definition for Bar::X should work, but instead yields a segmentation fault :-(

<php> public static function X() { forward_static_call('Bar::X'); } </php>