I have the old version mounted in the bento box, rubber-banded to the A-junction. It works just fine, broadcasting to the computer mounted on my bars.
(On my roadie, a TCR, it's in the seattube and also works, but BT might not be as good transmitting through the frame as ANT+).

So, you have two easy spots to mount it: in the bento or in the front headtube cover. I bet either would work.