tell document 1 of application "QuarkXPress" 
  activate 
  repeat with i from (count of pages) to 1 by -1 
    make page at after page i 
  end repeat 
end tell 

tell application "QuarkXPress" 
  activate 
  set bSpread to spread 2 of master document 1 
  tell document 1 
    repeat with i from (count of pages) to 1 by -1 
      make page at after page i 
      set master spread of page (i+1) to bSpread 
    end repeat 
  end tell 
end tell 

set bSpread to spread 7 of master document 1