Multiple instances of FckEditor 2.6.3 (nightly) and Ajax

Hi there! I'm simply loosing my brain trying to fix a nasty bug with FCK. Basically I have two FCKeditor created with javascript invocation code (but even if I try to invoke them with PHP the situation is the same). These editors are instanced with different names, for example description and article. Since are on my admin-side I prefer to use Ajax so i try to catch the data using FCKeditorAPI as mentioned in tons of post || pages of documentations of FCK. To get the rendered contents i'm using this function (found in this forum, I think)

function getEditorValue( instanceName )
{
    // Get the editor instance that we want to interact with.
    var oEditor = FCKeditorAPI.GetInstance( instanceName ) ;
    if (!oEditor){
        alert ("No instance named: " + instanceName)
        return;
    }
    // Get the editor contents as XHTML.
    return oEditor.GetXHTML( true ) ; // "true" means you want it formatted.
}

The strange thing is that if I have only one istance, for example description, it works. If I have two istances (description and article) sometimes it's working (10%) sometimes works only the first one (80%) and sometimes only the second one (10%). I noticed that this "bug" is common since surfing over the net a lot of people came across it. But the strange thing is that this bug seems to be "omnipresent" since I can reproduce it with any version of FCK, nightly too. So I wonder why create an instantiable object when you can use only one of that instance?

I'm stuck right now! I use firefox 3.0 with windows vista, cleaning cache often than washing my hands, and firebug listening on production site. The security.fileuri.strict_origin_policy is set to false, too. I don't post (yet) a ticket since as far as I can understand this problems should be already fixed in 2.6.3!