Unfortunately, you can't use an address in replace of a pubkey.

An address is a one way hash of a pubkey. Its not possible to use an address because it cant be used to generate a pubkey, and its the pubkeys (which is included in the redeem scripts) that are needed to validate the signatures in a transaction when you release/send the coins from your mutlsig address.

If you want to find a pubkey, of an address in bitcoin-qt then, click help, then click the "Debug window", then choose the console tab, and finally enter the following command:


The console will then output some data, including a pubkey. You will only be provided pubkeys for addresses in your wallet.

I will add these instructions to the page very very shortly.