same here. was there supposed to be something coming back?
Nope - you have created MasterCoins via your transaction, and you own them until you publish a message sending them to somebody else.
So how do I access them?
Well, right now you can see how many you bought using the GreaseMonkey script, or you can send them to someone else using a standard bitcoin client. You'll need the MasterCoinAdviser software to tell you the proper format of your send transaction. Links to download the appropriate software can be found here: https://bitcointalk.org/index.php?topic=265488.msg2841329#msg2841329