Vacuum filter 300sd?
 

I removed this vacuum filter earlier today (located on the driver side of the engine, close to the shock) to see how dirty it was and I cannot remember which way it is suppose to go???? How stupid of me.
Anyway it's done and I need some help. There is an arrow on the filter indicating the flow. Should the arrow point towards the front of the car (vacuum pump) or toward the rear of the car (driver)?

I took some pictures:

http://gallery.me.com/flangenard#100511

Thank you.