按道理 将记住密码checkbox的 id设置为 RememberMe 即可实现，但不生效。

配置文件启用了Membership 和角色管理 ， 用户管理，角色管理都没问题。 

cs不用写代码，登录正常，就是不能记住密码。

验证配置如下：
<authentication mode="Forms" >
      <forms loginUrl="Manager/Login.aspx" name="AdminLogin" timeout="60"></forms>
    </authentication>

Login代码如下：

<asp:Login ID="Login1" runat="server" BackColor="#EFF3FB" BorderColor="#B5C7DE" BorderPadding="4"
            BorderStyle="Solid" BorderWidth="1px" Font-Names="Verdana" Font-Size="9pt" ForeColor="#333333" 
            FailureText="用户不存在或密码有误,请检查后重新输入!" LoginButtonText="登录" PasswordLabelText="密　码:" RememberMeSet="true"
            RememberMeText="记住密码" TitleText="用户登录" UserNameLabelText="用户名:" DestinationPageUrl="~/Manager/ManagerDefault.aspx" OnLoggedIn="Login1_LoggedIn">
            <TitleTextStyle BackColor="#507CD1" Font-Bold="True" Font-Size="0.9em" ForeColor="White" />
            <InstructionTextStyle Font-Italic="True" ForeColor="Black" />
            <TextBoxStyle Font-Size="0.8em" />
            <LoginButtonStyle BackColor="White" BorderColor="#507CD1" BorderStyle="Solid" BorderWidth="1px"
                Font-Names="Verdana" Font-Size="0.8em" ForeColor="#284E98" />
            <LayoutTemplate>
                <table border="0" cellpadding="0" class="TMM_TblStyle" style="width: 300px;">
                    <tr>
                        <td align="center" colspan="2" class="TMM_Tbl_Title">
                            用 户 登 录</td>
                    </tr>
                    <tr>
                        <td align="center" style="height: 35px; width: 104px;" >
                            <asp:Label ID="UserNameLabel" runat="server" AssociatedControlID="UserName">用户名:</asp:Label></td>
                        <td style="width: 154px; height: 35px;">
                            <asp:TextBox ID="UserName" runat="server" CssClass='TextCursor'  Font-Size="9pt" Width="119px" onkeydown="Searchkeydown();"></asp:TextBox>
                            <asp:RequiredFieldValidator ID="UserNameRequired" runat="server" ControlToValidate="UserName"
                                ErrorMessage="请输入用户名." ToolTip="User Name is required." ValidationGroup="Login1">*</asp:RequiredFieldValidator>
                        </td>
                    </tr>
                    <tr>
                        <td align="center" style="height: 35px; width: 104px;">
                            <asp:Label ID="PasswordLabel" runat="server" AssociatedControlID="Password">密　码:</asp:Label></td>
                        <td style="width: 154px; height: 35px;">
                            <asp:TextBox ID="Password" runat="server" CssClass='TextCursor' Font-Size="9pt" TextMode="Password" Width="119px" onkeydown="Searchkeydown();"></asp:TextBox>
                            <asp:RequiredFieldValidator ID="PasswordRequired" runat="server" ControlToValidate="Password"
                                ErrorMessage="请输入密码." ToolTip="Password is required." ValidationGroup="Login1">*</asp:RequiredFieldValidator>
                        </td>
                    </tr>
                    <tr>
                        <td align="right" style="height: 20px; width: 104px;">
                            <asp:CheckBox ID="RememberMe" runat="server" Text="记住密码" />
                        </td>
                        <td align="center" style="height: 18px">
                            <asp:Button ID="LoginButton" runat="server" BackColor="White" BorderColor="#507CD1"
                                BorderStyle="Solid" BorderWidth="1px" CommandName="Login" Font-Names="Verdana"
                                Font-Size="10pt" ForeColor="#284E98" Text="登录" ValidationGroup="Login1" />
                        </td>
                    </tr>
                    <tr>
                        <td align="center" colspan="2" style="color: red">
                            <asp:Literal ID="FailureText" runat="server" EnableViewState="False"></asp:Literal>
                        </td>
                    </tr>
                </table>
            </LayoutTemplate>
        </asp:Login>