Hey guys, it is not possible to control the sender address from which the BTC are sent out (Input of a transaction)
yet.
When you send bitcoins to someone else, the reference bitcoin client bitcoin-qt chooses on his own from which of your addresses the coins will be send from.
There exists a long time requested feature to give this ability to the Bitcoin users which is now called "Coin Control", and should be working stable enough to release into version 0.9 of bitcoin-qt :-)
Have a read on
https://bitcointalk.org/index.php?topic=144331Do not be excited if you see an address sending your payment out, which is not in your list of receiving addresses: Bitcoin client often sends parts of the transaction sum back to an address of your wallet which is not shown to you.
For example if you only have single payment of 2BTC in your wallet received, but you want to send 1BTC out. The other 1BTC gets back to your wallet to a new address, because there was only one possible unspend output (2BTC) usable as input for the 1BTC transaction.
So you will be able to supply the sending address as soon as you can control from which address of your wallet the payment will come from :-)