300TD hatch strut (+ non-existence)?`

[blankenship]

i've got a 1980 300TD that from all indications has never had a "hatch strut:" (the thing that keeps the rear hatch in an "open" position and prevents it from having to be held open or from bonking you on the head).
i've seen that you can order the strut for $55 or so, but i have no idea how to install it, as there is NO noticable place for it to fit or screw in.
does anyone know if my model will accept the strut, or does anybody have instructions or pictures of how/where the strut's installed on their wagon??
thanks!!