Ah yes, I forgot that you were using a Windows message instead of a shortcut key. The message to send is 0x41a (1050), so your 2nd SendMessage call is correct (the 1st one isn't), assuming the window handle is correct.
Ultimately, the Windows message and shortcut key methods run the same code (the Windows message triggers a shortcut key action), so if one works then so should the other. If the message still isn't working for you then please try setting a global shortcut and see if that works.