Thanks for the reply.
My problem is not just ISP blocking. They only block 4 ports. I can use others in my ip cam without problem. But I plan to view the cam from my office, which blocked ALL ports except 80. Blocking on both sides and without a commonly opened port made me post my problem here.
Is there a way that make my ISP believe that I am using 8080 while, at the same time, my network admin believe that I am using 80? Must in-bound and out-bound traffic use the same port?