Ok. I had to do this to, and it's easy.
Turn the ignition to 1 or 2, turn the wiper on, when the wiper is on the passenger side of the vehicle, take the key out so the wiper stays where it was left when car was turne off (ie passenger side of car). Then remove cover, lubricate, and you can guide the wiper manually when it's left like that and not in the parked position. GOod luck.
2006 E350 w/ 155k miles (Daily Driver)
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)