Customization of Del was requested on the ML . The trick is to assign an action to "Delete Content" (thanks Piet for finding this) though it would be more transparent for the user when Del itself has a clear assignment in the first place (apparently to this command).
Heiko, could you write your suggestion in detail?
(In reply to Roman Kuznetsov from comment #1)
> Heiko, could you write your suggestion in detail?
Please elaborate it a bit more...
Moving to NEW...
We need an UNO command in order to allow customization. More info in the referenced post to the mailing list.