Setting up a reverse proxy to route around ISP block of inbound port 80 traffic

For some local web development that receives callbacks from an external source (Twilio API), I needed to open up my firewall's inbound port :80. It turned out my ISP's consumer-level account prevents traffic on port 80 but allows inbound traffic on 8080. So, I wanted to set up a proxy on my remote VPS running cPanel/WHM but could not crack it. Can anyone help?

The long and the short is, I would like to be able to receive traffic on subdomain.mydomain.com:80 at the VPS, have it forward *as* anysubdomain.mydomain.com:8080 to be *port-forwarded* to :80 on my internal. I've got a handle and complete control over the last step (port forwarding is simple), but how to set up a transparent reverseproxy on cPanel eludes me.

Thanks
-Bronius