use of RenderControl

[ton]

Hi,

can someone explain to me how and when to use RenderControl. This is what I
want.

I want via Ajax to call a procedure in which I can Add a control like a
datagrid and then add this control of the rendered output string to a panel
of what ever.
I m currently trying to use the ajax modal popup. But the data to show on
the modal "form" is different and would be displayed in customserver
control. Loading another form is easy, just use the query parameters and
show the result, but with the popup I can have the parameters, but the
webservercontrol isnt updates.
So I moved to use an extra panel as the dynamiccontrolid to fill this panel
with the data. This works but ..... it is just plain text, the heading is
not anderlines and so on.

Can someone help me a bit further?


Thanx


ton