Correct me if I am wrong about this, but I do not believe that you can vote on line. The notice says that the proxy statement and the form of proxy will be mailed to all stockholders on or about August 4, 2011.
From what I have seen in the past, the proxy statement contains the evidence of shares provided by the brokerage. This evidence is necessary as of the cut-off date per the notification.
"Only stockholders who own shares of our common stock at the close of business on August 1, 2011 are entitled to notice of and to vote at the special meeting."
Doesn't look to me as though there is an on line option.