binding "<escape> <kp-delete>"

[Maverick Woo]

This is Emacs 24.3 on OSX GUI.

The default installation maps kp-delete to 4 (C-d) in local-function-key-map. 
This works as intended. But if I press "<escape> <kp-delete>", it gets 
translated into "C-M-d", which is down-list for me. Instead, I want it to do a 
forward kill word.

The problem comes when I try to bind "<escape> <kp-delete>". The farthest I got 
is as follows, but it has a significant drawback:

1. erase it in local-function-key-map first:
(define-key local-function-key-map (kbd "<kp-delete>") nil)

2. to get back the no-modifier behavior, this works:
(global-set-key (kbd "<kp-delete>") 'delete-char)

3. suppose delete-word is the function I want to bind to:
(global-set-key (kbd "<escape> <kp-delete>") 'delete-word)

The problem with this method is I break the "<escape> ==> meta" translation. In 
particular, after step 3, the other keys like "<escape> x" will not get 
translated into M-x any more. So I think step 3 should not be done.

Any hint on how to bind "<escape><kp-delete>" properly?

Thanks.