<div id="myTst" runat"server">
    <asp:label id="lbl1" Text="Hello" runat="server" />
    <asp:label id="lbl2" Text="World" runat="server" />
</div>

Dim myPlaceHolder As ContentPlaceHolder = DirectCast(Master.FindControl("ContentPlaceHolder1"), ContentPlaceHolder)
    Dim cntrlDiv As HtmlControl = DirectCast(myPlaceHolder.FindControl("myTst"), HtmlControl)