You probably referred to my faucet at http://xcp.bfolder.com/ , right?

Yes, you can use the BTC address you have on your forum profile, but you need to be able to sign a message with it.
Put your user_id, and the signed message on the faucet web, and it will crosscheck with the BTC address on you forum profile.

Once you get the giveaway XCP, you may import it to the counterwallet later if you like.

(Reason for signing is to prevent people from using btc addresses from exchanges or shared web wallets, which they will never be able to transfer it out)

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Counterwallet used to be able to sign message compatible with bitcoind, but last time I checked they were incompatible. If the problem was fixed, you should be also be able to use Counterwallet address to claim directly on the faucet, and don't need to import it.