Hi, no there's no special secret handshake: this should work right from the get-go (and yes, I just tried it out with MIDI Designer Lite 1.3.8 [the version you have] to make sure I'm not going insane).
So we're back to normal diagnosing, but we will figure this out.
Please create a new Session under "My Sessions" under MIDI Network Setup on your Mac. Give it a special name, like, "What Is Broken?" CHANGE THE BONJOUR NAME TOO.
Do NOT connect the iTouch MIDI Monitor to it. Only connect MIDI Designer to it. In fact, close the MIDI Monitor app entirely (for now).
These steps, while arbitrary from a diagnostic point of view, might get us closer to understand what we're missing. This is truly weird but I believe we will track it down. Please note ANYTHING that is weird, like the Bonjour Name not showing up correctly on the iPad, etc.
There's a chance that your binary is broken in this one particular way, but the chances of that are about the same as the chances of somebody just randomly showing up at my door with the food I want to eat without me calling anyone. Oh wait, I hear a knock.
In all seriousness, thanks for your patience as we figure this out. We will.