SignRawTransaction - What is scriptPubKey and redeemScript? [SOLVED]
First of all, take a look at https://gist.github.com/gavinandresen/3966071.  That's a script that creates two raw transactions: one to fund a multisig address, and another to spend the funds.  It shows each of the steps necessary to create and spend from a multisig address.  Unfortunately, the script doesn't do a good job of explaining where the parameters come from.  I'll try to explain the parameters you need.

As you guessed, hexstring is the output from createrawtransaction, and transaction id is the ID of the transaction that sent the coins to the multisig address.  redeemScript is easy.  When you first generated the multisig address, the command returned both the address and the redeemScript.  If you don't have that value, you can recreate the multisig address with the same public keys and you'll see it in the output.  scriptPubKey is the one I'm not sure about.  I think I know what it is, but I don't have bitcoind in front of me so I can't be sure.  If you decode the raw transaction that send coins to the multisig address, you'll see one or two outputs, one of which sends coins to the multisig address.  (The other output sends the rest of the coins to a change address.)  There will be a scriptPubKey section in that output.  Copy the hex string from that section and use it as the scriptPubKey parameter.

Once you have those parameters, you can sign the raw transaction and send it.  If it doesn't work, leave a comment here and I'll try to work it out when I get home.