I run a pool and haven't ever seen any stake in my pools TEK wallet, is there some secret to enabling staking or isn't it supported in the command line wallet?
My other theory is coins sent for mining payments are the 'oldest' in the wallet so I never have any of the same coins there for over 30 days. I've always got a balance in the wallet, i.e. its never empty so should I technically be receiving stake or not?
I don't have an official answer, but I would guess that you don't have coins in long enough. It takes a bit over 30 days. As far as I know, there's no "secret" method nor anything that requires the QT wallet, but if you don't see it as a security risk, you might try running QT instead of the daemon, just set up as a server. It's coin control features will allow you to set the priority on coins and only spend the newest mined or minted coins. This is probably doable from the command line as well, but I have no idea how

I know the coin control is either the same or very similar to hobonickels, so you might check their wiki. Also, if I understand it correctly, the wallet has to be unlocked for it to stake. Which might pose a problem for a pool.
In a far less dynamic environment, I have gotten stakes from both the older wallet prior to presstab and Tranz becoming involved, and the new one. QT in both cases, so I don't know if that applies or not. I do know that the staking algorithms work.