How to avoid manipulation of automatically inserted html?

[jawosis]

Hi,
after inserting a prefilled span (html content is automatically generated) to the editor window I wan't to prevent further editing of the span's content. Thus I need to...
1) Get the cursor out of the span container right after inserting its html content (by default the cursor maintains inside the span)
2) Trigger deletion of the whole span container once the cursor deletes a part of the automatically entered span html

How can I achieve this?

[jawosis]

I forgot to mention that I also would like to prevent the editor to change the prefilled span html.