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Since Apple doesn't provide any public API for putting monitors to sleep or offers any way to configure the keyboard shortcut for this functionality, either, I'm afraid I can't help you in this case. Sorry.
Well, the authors of SleepDisplay and DisplaySleepr apps managed to do that somehow. So it's doable.
Sure, it's doable - but not through emulated keystrokes / _public_ APIs. It's only doable through _private_ APIs. Which - in this particular case - if called under older OS X releases (10.4 in particular), leads to a kernel panic. This alerted me. There's no guarantee why the same couldn't happen under new OS releases. There's just no way to know - nobody can look into the future.
The risk of crashing may be acceptable for freeware, but it's not acceptable for a commercial product like Remote Buddy, which is built on public, documented APIs for maximized stability.
It's not that I haven't looked into it.
Best regards,
Felix Schwarz