passing a variable to choose file dialog box?

Hello All

Need some advice again firstly here is my code:

set the this_folder to POSIX(choose folder with prompt “Please select the folder which contains the Indesign files to convert”) as alias
on error
set the this_folder to path to desktop as alias
end try

tell application “Finder” to set the_files to every file of the this_folder whose name extension is “qxp”
repeat with oneFile in the_files
tell application “QuarkXPress”
delay 5
tell application “QuicKeys”
play shortcut named “ID2Q Open”
end tell
end tell
end repeat

I have an extension that has its own menu in the main menu bar I could not access it via normal applescript or GUI scripting. I have gotten myself a copy of Quickeys which has solved my problem with getting to the open file dialog box for the Quark Extension. The menu is a follows:

Main menu bar → Markzware → ID2Q – > Convert Indesign Document —> open file dialog box

I have declared a constant of the this_folder at the beginning of the code. Is there a way to pass this path to the open file dialog box through applescript? quickeys cant do it and I cant access the menu without quickeys. I really need to have the script select all files with the extension of indd in the path chosen in the beginning of the script.

It is crucial that this is fully automated as this process will be running without human intervention for quite a while