@Bob, that works for me too. I tried a quick puff but that didn't work. Blowing into the mic for 2 seconds does the trick for me! And I'm using the boom mic.
I own the SMH10 with built-in speakers and mic. And, like many others, I'd like to have the "MP3" jack drive my earbuds instead of the speakers when I plug them in (i.e., speakers on when no earbud...