New rare/key items

So, I'd like to make a new "Diving Helmet" rare/key item that you get during the scene with Gau at Crescent Mountain. However, even after studying scenes where key items are added, I don't understand how it's done. Is it just an event flag? If so, do we know which flags are tied to which unused key items?

Does anybody here have any insight into this?

Thanks!

Novalia Spirit's document here list all the event bits, both used and unused: http://novaliaspirit.99k.org/ff6/file/ff...t_bits.txt

1D0 BA:0 Rare item: Cider
1D1 BA:1 Rare item: Old Clock-Key
1D2 BA:2 Rare item: Fish ("A yummy fish")
1D3 BA:3 Rare item: Fish ("Just a fish")
1D4 BA:4 Rare item: Fish ("A rotten fish")
1D5 BA:5 Rare item: Fish ("Fish")
1D6 BA:6 Rare item: Lump of Metal
1D7 BA:7 Rare item: Lola's Letter
1D8 BB:0 Rare item: Coral
1D9 BB:1 Rare item: Books
1DA BB:2 Rare item: Royal Letter
1DB BB:3 Rare item: Rust-Rid
1DC BB:4 Rare item: Autograph (unused)
1DD BB:5 Rare item: Manicure (unused)
1DE BB:6 Rare item: Opera Record (unused)
1DF BB:7 Rare item: Magn.Glass (unused)
1E0 BC:0 Rare item: Eerie Stone (unused)
1E1 BC:1 Rare item: Odd Picture (unused)
1E2 BC:2 Rare item: Dull Picture (unused)
1E3 BC:3 Rare item: Pendant

When one of the bits gets set, the rare item will pop up in your inventory.

AWESOME! Thank you very much!!!