extending interfaces - fringe behavior

I have a need in a current application to extend interfaces and possibly re-define (change signature) some of the inherited methods in the child interface. e.g. interface Foo { public function __construct(MyCls $var); public function myFunction(); } interface Bar extends Foo { public function __construct(MyCls $var, $var2 = null); public function myOtherFunction(); } class A implements Bar { public function __construct(MyCls $var, $var2 = null) { // ... } public function myFunction() { // ... } public function myOtherFunction() { // ... } } This is not currently possible in PHP5b4, due to the (new?) "Can't inherit abstract function" errors generated by the engine. I.e. if I try to redefine __construct() I will get an error. The need for this capability is probably not that mainstream, but it'd be very nice. Is there any chance of having support for this behavior? I don't know anything about the underlying mechanism for supporting interface extension, so I don't know if what I'm asking is trivial or not. Thanks, Hans