SAP Enterprise Portal 7.0 : Portal Access from the outside

Dear experts,

i have installed a SAP Enterprise Portal 7.0 stack JAVA on Windows Server 2003 Enterprise 64bits with MS SQL Server on a Virtual Machine (VM) and i can access to the link http://<loaclhost>:5<Instance Number>00/irj/portal without problem

My network administrator network has only opened the port 80 and from the outised i cannot access to my portal weblink.

How can i access from the outside knowing that i must pass through the port 80. Please help.

Thank you very much.

Best regards,

Pascal.