getting selected text with format

Hi,
I am trying to get the selected test, modify it, and update the selection accordingly. But I am encountering trouble: I do cannot figure out how to obtain the selected text including also the formatting HTML tags.

Searching this forums, and the web I have found examples like this one:

editor.getSelection().getNative().toString()

( I cannot use this since all the HTML tags marking bold, italics, etc are lost);

and this one:

editor.getSelection().getStartElement().getOuterHtml();

This one gets me the HTML, but not just the SELECTED one.

Could someone, indicate-me, please how to get the SELECTED HTML only ? I am using CKEDITOR 3.6.2

Thanks