how can i set scroll in the right in FF3

i have a multiline textbox
and it have scroll
 

<asp:TextBox ID="txtMessage"   runat="server" TextMode="MultiLine"  CssClass="DtxtMessage"ClientIDMode="Static" Wrap="true"></asp:TextBox>

 
in i.e 7,8 and FF 6 scroll in the left of textbox
but in FF 3 scroll in the right
 
how can i set scroll in the right in FF3
 

.DtxtMessage
   {
      -moz-border-radius: 5px;
          -webkit-border-radius: 5px;
          border: 1px solid   #ffffff;
             direction:rtl;
          font-family:Tahoma;
          background-color:Transparent;
         color:White;
        margin-right: 0px;
       }