This won't work without changing the router settings, which I think the school won't like doing.
I'd try to find a different way to do this if possible. Do you have the possibility to upload to a "shared" directory somewhere in the school, from which you can access outside the school?
Ask the system administrator in the school, he's really the only one who can answer your question.
Your thinking that it's simply a matter of getting the right link is incorrect. The traffic is being blocked by the router (Which is exactly what it's supposed to do).
Shane.
Using LV 6.1 and 8.2.1 on W2k (SP4) and WXP (SP2)