How to access special keys using a ZAGGmate keyboard with iSSH on the iPad?
I've developed a terminal for iOS (it is not released, is intended as a base for other projects) and I have tried for hours to see any kind of event or modifier when meta keys are used on an external keyboard. The only way to get these events is to use private APIs and if you do that you can't get your app on the store. I have filed an issue (Apple rdar 10283552) and hopefully this will change in a future release.

So the problem is not your keyboard, it is iOS. I think you have found the best solution with key chords, unless you want to use one of the better apps like Prompt, which gives you "soft" meta keys on the screen - but the whole point is to keep your hands on the external keyboard, I know.

I don't know for sure if Prompt keeps those meta keys visible when a BT keyboard is connected - it can be done in code - if it did maybe soft metas would be better than nothing.