Web Forms :: Parsing Html From Ckeditor And Inserting Usercontrols In The Text?

I am trying to add some widget-functionality to the CKEditor using custom plugins.. Does anyone have any experience parsing the resulting html or getting the job done in another way?

What I am looking for is to add something like a news-block at a user specified place in the text, like an ordinary image..

I have thought of several options, like just adding an iframe that takes care of the content automatically (from the src url in the iframe), but that way I loose the text formatting/css.. I have also thought of adding the content dynamically with some ajax onload, but that way I might loose some viewers..

Finally I have come to the conclusion that using custom tags like <something options="..." /> or even <div class="something" options="..."></div> and then replacing them with usercontrols is the best solution.. But how to accomplish this? I know how to add controls to other servercontrols, but how to add them easily in some random text? It could be something like putting the text prior to the widget and after into a placeholder and adding the widget-control in between..