FCKeditor Contents

I am using the FCKeditor in an ASP .NET page. The contents of the FCKeditor when the .aspx page is loaded are populated from a session object that is set by the calling page. I am trying to mimic the preview functionality already present in the FCKeditor with my own custom logic. I have a custom plugin which appears as a button on the FCKeditor toolbar and when I click it it popups a new windows with the HTML preview of the contents of the FCKeditor. Is there anyway in which I can have my session object catch the changes I make in the FCKeditor so that the new preview window which popups up will reflect my changes ?

Thanks in advance.