Oil Filter location 2003 C230K Sports Coupe

[Pffarin50]

Hi all,
This is my first entry onto this forum.
I purchased after leasing my 2003 230 K Sports coupe in 2006.While under warranty the dealer performed A and B service. Now at 24,000 miles, for the the 2nd time, the A service wrench came up. I plan to NOW do my first Benz oil change. Paying the dealer 300+ is rididulous. I had no problem resetting the counter as per the owner's manual.
From reading these forums I purchased a Mytivac extractor 2.3 gallons, 12 Qts 0W40 Mobil 1 Synthetic and the correct Mann oil filter elements.
I found the dip stick opening for extraction but can't locate the oil filter cap location which covers the oil filter element.
On the right back wall I did discover a bell shaped black cap with a hex nut holding it in place. The nut has an arrow on it going clockwise. I think that this may be the location of the oil filter.
If it is, can I use a rachet socket to loosen it or must I use a special tool,
If this is not the filter, does anyone know where it is.
I've done oil changes for over 40 years and never had a problem like this before.( maybe because I never owned a Benz)
If anyone could help me out that would be great.A diagram or pic of the filter location would really be SUPER!
Finally, does the 230K sports coupe has a drain plug from the pan? Is their a dip stick that can bought and inserted into the dip stick opening?
Since 2003 the car has run great except for an alternator( by dealer) replacement in 2005 and a burned out bulb. I've read some interesting threads about this car and hope that I don't have the same problems.
Thanks
Paul