Having trouble with ASP.NET 4 RadioButton GroupName property

Hello,
I think I found some bugs on the asp.net 4 RadioButton control rendering.
Firstly, I don't understand why the "Value" property was removed from RadioButton control? What a reason?

Secondary, why the "GroupName" property of RadioButton control changed after render? This property must be a static!!! This situation is a same then we try to use the HtmlInputRadioButton. For example, if we have the aspx file like
<body>
    <form id="form1" runat="server">
    <asp:RadioButton GroupName="rList" id="rbAsp"...> 
    <input type="radio" name="rList1" id="rbHtml"...>
    </form>
</body>


on the resulted HTML we will have something like this:
...

<input type="radio" name="ctl00$r ...