How to serialize an extended property for a Webcontrol?

[Stefaan V.]

Dear all,
I created a webcontrol that makes use of an extended property which I want
to serialize or dynamically add in the InitializeComponent method.

E.g. Suppose I created a Help Provider and dropped it on my webpage. This
controls adds an extra Help property to the web controls on the page.

Now I want that when I close the web page that the Help values I set for
each control to be serialized either as an attribute in the respective
control (e.g. <asp:Label id="lblX" help="Help me" > or something like
HelpProvider.SetHelp(lblX,"Help me") in InitializeComponent.

I already tried DesignerSerializationVisibility(combined with default value)
but it doesnt work. When I
use similar code for Windows Forms it does work. Any ideas ?
Thanks in advance!
Stefaan