Oh, then that would be different from Novacoin - there you can do it once but then you see errors in the log because of trying to use an invalid txid as input (something like that, it was a while back I last did this and refrained from doing so since then). It would be included in the next block after the block in which the first one will be included, though. But the client would not let you create more than 2 of these transactions, because then coin control would be confused. That's why they added a feature to not select zero-confirmed transactions as transaction inputs.
If you managed to solve this with HYP, then that's a fine thing :-)