Keynote keyboard shortcut for Add Link and Edit Link
I'm trying to modify the shortcut on the Keynote program.
I want to map the "Format->Add Link->Webpage" to "cmd+k", which is by default mapped to "Format->Add Link->Slide".
By default, when an item that has a link is selected, the "Format->Edit Link" menu item gets enabled (and Add Link disappears) which is mapped to the same "cmd+k". I want to keep this as it is and only change the "Slide" to "Webpage" of the "Add Link" menu.
But when I create both these shortcuts in the keyboard settings,
1) "Format->Add Link->Webpage" to "cmd+k"
2) "Format->Edit Link" to "cmd+k"
the Edit Link shortcut doesn't work (it doesn't get created).
I know that you can map two complementary menus to the same shortcut, because for Safari, I mapped both "View->Show Bookmarks Sidebar" and the "View->Hide Bookmarks Sidebar" (which conditionally appears when the bookmarks sidebar is shown) to the same key mapping "cmd+shift+b".
So why doesn't it work for Keynote, and what can I do?