Can't use action-combo key-bindings in Xcode 4?

I'm using custom Cocoa text key bindings (as explained here) using the ~/Library/KeyBindings/DefaultKeyBinding.dict. One of the bindings does the equivalent of these commands:
- move to beginning of line
- kill to the end of line
- forward delete
so it works just like Ctrl+L from Visual Studio, which deletes the entire current line and shifts everything below up.

It works on most OSX-native apps, but not in Xcode 4 (it works in Xcode 3 too)! Any workaround other than trying another text editor?