I checked your stats and you have a potential of 56 activity which is far away from full member. Another thing that i saw it that you haven't posted any bitcoin address so you can't prove that you are the owner of that account, have made any deal with any member here, even through PM?
I have made a 0.15 bitcoin trade, where I sent first to a trusted member and the transaction went smoothly. But I never had to sign a bitcoin address.
In this case you should provide to the buyer the signed message from that address and require from the seller or buyer that you traded to confirm, that's all, good luck with sales.