Thanks!Should I plus rep or negative rep? Looks like your gathering -rep so...
I got it working...After a few tries is easy!From the roof I run and jump on the landers computer once a friend calls it back.You can stay there and zombies can't get you.Also once my friend used it I was able to jump off at any point.Getting to the close PAP room.

Ofcoarse most of you know this.
It was hard at first but this is what I do:
1.)Have Juggernog and Phd Flopper
2.)Call the lander to where the Phd is.
3.)The side you want to get on is opposite of the Phd flopper machine.(near the wall with Frag. Grenades)
4.)Get as close as you can to the terminal so the buying option shows up.
5.)Hold square or X(depending on system) and walk backwards quick.
6.)Lander should be taking off without you in it.
7.) Quickly while it is getting ready to take off, after you walk backwards go prone as close as possible to the yellow line on the ground.
8.)While prone, to make sure you did go on the rim of the lander hit forward on your analog stick so your character moves towards it.
9.) If it works you will be on the lander still prone or not.If your prone wait until the lander is at it's highest point and move the analog stick down.This will cause you to move back and off the lander and you SHOULD land on the roof.
10.)Now do whatever you want!
Hope this helps because apperently alot of you can't get it to work.For me it worked and it is actually pretty easy. I used these exact steps so I'm putting them out there.
I guess I can help a few people out if they need help.Though I'm not going to be using my mic...Hopefully is not patched when I go back on later... PSN is K-oTiC_GuNNeRz