1) Choosing the withdrawal address from your own wallet.
2) Copy and paste "I_sell_account_*******_for_*****_BTC", without quotes, without spaces...
3) Sign the message.
4) Copy and paste the signature.
Every sell request until now has been fulfilled properly. If you can't follow these simple steps I don't know how to help you. Read again the instruction and try, if it doesn't work either you are doing the wrong procedure or the wallet you are using is flawed.
I wish to change an address that came from MtGox, at the time - or I simply didn't read carefully the address I used for payout was a one off. However I have for the past year been receiving Bitcoin from you. Now I wish to change it I am stuck for a signature. Where if at all on the Mt Gox site do I obtain a Signature for an address that is no longer shown? Is there another way?
' Support, Feb 21 04:56:
Dear Valued Customer,
Sorry for the delay in response as we had huge volume of support tickets and we are working hard to resolve this.
I will help you with your query. Please note that we do not have any signed messages for bitcoin deposit. Use your bitcoin address and then transfer the bitcoins. You can find the bitcoin address of your account with these steps: Trade->Funding Option->Add Funds->Bitcoin, then you will notice the bitcoin address at the bottom of the page.Please get back to us for further assistance.
Best regards,MtGox Team'
There seems to be no way of getting one for such addresses - no wonder the hell broken loose. I do have private csv files with all the history of deposits, if there is another way, by which I can email you proof of ownership of the address.