AJAX :: Reading Binary Data Using Asyncfileupload Control?

i am using AsyncFileUpload1 control

<asp:UpdatePanel ID="upSummerization" runat="server">
<ContentTemplate>
<div id="divFileUpload" runat="server">
<asp:Label ID="lblAttachDoc" Text="AttachDocument" runat="server"></asp:Label>
<cc1:AsyncFileUpload ID="AsyncFileUpload1" runat="server" />
</div>

i want to read bytes from uploaded document usning this control but i am get bytes length 0

Dim bytes As Byte() = New Byte() {}
Dim fs As Stream = Me.AsyncFileUpload1.FileContent
Dim br As New BinaryReader(fs)
bytes = br.ReadBytes(fs.Length)