get into the private campus server

Ok.... heres how it goes, I set up an ftp server from behind the
school's LAN. This works all fine and well anywhere on campus, you know
in a computer lab we are all able to get back to the server which is in
the dorm (same Class B range of ips) but on a different subnet... I
have a friend who wants to access the FTP from his house (off campus)
and take advantage of the wicked upload speeds that schools network
provides. We have it set up for SFTP, FTP and SSL but naturally cannot
access any of this when we are off the schools ip network. The cisco
router that i am behind.... and this is only as i understand it-hides
the ips from any outbound incoming connection.

Here is what we have tried. Using all different ports as in 25 and 80
in an attempt to get through an smtp or http opened port but i highly
doubt they would leave these ports open for the dorm's internet because
per say they wouldn't want us hosting an ftp server.... or something
like that. All pings sent to the dorm sever come back perfectly so if
anything is "hidden" its a relative term.

My thoughts. I have told the people that want to get to the sever from
outside the schools network that they were just sol, but if pings are
coming back then there must be some way it could work. I also have a
phone line thats free of charge to me so i wonder if it is possible to
have someone dial in and establish a connection to the off campus
computer (ie the campus computer would effectively connect with the off
campus pc and then allow the off campus pc to do all the talking)

I am a 4th semester UNIX Computer Networking Systems and all of this
would be no problem if i could break into that router closet downstairs
or hold the student online services lady hostage for the routers
password, obviously these options are kinda last resort. If you have
any thoughts as to how we could make this work fell free.... nay feel
obligated to drop a line.

.