Problem with integrating FCKeditor in javascript with Ajax.

There is described some ways how to integrate FCK with javascript.

http://wiki.fckeditor.net/Developer%27s_Guide/Integration/Javascript

We have 3 steps how to do it. But in my situation does not suit any of them.

My situation is: I have textarea where is loaded text and user have two ways how to use FCK, with button, its OK it is function with the step 2 in tutorial and method oFCKeditor.ReplaceTextarea() ;

Next way is to choose item and the text is dynamically loaded by Ajax so I need ReplaceTextarea with value getted from Ajax, in Firefox I can change the value of textarea and replace it, but in IE the replaced FCK hasn´t got any value.

Has anybody some ideas?

Thanks for help.