I have a same car. I followed the instruction from Ford repair manual and successfully removed mine.
Raise the wiper pivot arm off the rear glass and pull the latch lever out away from the wiper arm. then lower the wiper pivot arm towards the rear glass. please note the wiper should not touch the glass if you let it go. otherwise, repeat the first step. Now you can remove the wiper pivot arm out by pulling it outwards.
ian
June 2008