Anthem Library and FCKEditor -- How to update?

I writing a patch for recently finished admin panel, a product entry form.

I used Anthem in its front face and admin panel for user attraction. But FCKEditor's update status being a problem. I decided using Anthem_PreCallBack and Anthem_PostCallBack events in js so update the textarea (asp:TextBox) value with js do i can use at server-side this value. Sounds good, eh?

First, I use this way:

http://www.fckeditor.net/forums/viewtopic.php?f=6&t=4222

 But Firebug alerts, hmm this way doesnt work, i cannot understand why. How strange. How sad.

Then, I use more standard way: API there:

http://docs.fckeditor.net/FCKeditor_2.x/Developers_Guide/JavaScript_API

Example:

-----------------------------------------------------------------------------

function Anthem_PreCallBack()
 {
    //document.getElementById('<%=textboxSample.ClientID%>').value =
    //frames[0].objContent.DOM.body.innerHTML;
    var oEditor = FCKeditorAPI.GetInstance('<%=textboxSample.ClientID%>');
    document.getElementById('<%=textboxSample.ClientID%>').value =
        oEditor.GetHTML(true);
}

function Anthem_PostCallBack() {
    //alert(document.getElementById('<%=textboxSample.ClientID%>').value);
    //frames[0].objContent.DOM.body.innerHTML =
    //document.getElementById('<%=textboxSample.ClientID%>').value;
    var oEditor = FCKeditorAPI.GetInstance('<%=textboxSample.ClientID%>');
    if(document.getElementById('<%=textboxSampleIsEditing.ClientID%>').value.length>0)
    {
       oEditor.SetHTML(document.getElementById('<%=textboxSample.ClientID%>').value);
    }
    else
    {
        oEditor.SetHTML("");
    }
}

-----------------------------------------------------------------------------

textboxSample is our primary textbox. Other (textboxSampleIsEditing) is for we are in editing status. For example, if we are editing a row in database we dont want Anthem_PostCallBack reset the fields value. I setting this textboxSampleIsEditing value for different from empty string than js dont reset other textbox, get it? Yes its sucks but i cannot run other ways.

Hope this helps.