Indesign CS4: modal state unavailable (applescript)

Hi,

I have written an application in which I try to catch modal dialogs with this construct:

<code>

...

if modal state is true then

     set meinInDesignStatus to "modal"

end if
...

if meinInDesignStatus is "modal" then

     display alert("Please close the modal window in InDesign before continuing!")

end if

</code>

In the former version (for CS2) this code worked fine. But since I am trying to use this script with CS4 my alert is not displayed anymore. Inside the "ADOBE INDESIGN CS4 SCRIPTING GUIDE: APPLESCRIPT" I was not able to find anything like this construction.

Do you know any way to get this running again?

Thank you in advance.

Bests

Rolandd