How to add Note Board webpart to all pages

Hi,

My objective is to have the Note Board webpart on all pages of my Wiki Page Libraries.

The instructions i have found say the same thing:

http://www.sharepointbinder.com/1/post/2012/02/inserting-web-parts-in-sharepoint-2010-master-pages.html

(I am making sure to check in and that the new master page is set as the default master page)

My issue may be that I do not know where to place the webpart. I want to place it at the end of the page. But I cant even get it to show up in the mail area:

                            <div id="MSO_ContentDiv" runat="server">
                        <a name="mainContent"></a>
                        <asp:ContentPlaceHolder id="PlaceHolderMain" runat="server">
                        <p>&nbsp;PLACING WEBPART HERE</p>
                        </asp:ContentPlaceHolder>
                            </div>

Any ideas on what i need to do differently?

Thanks