Access Iomega Home Service through Airport Express

Hi,

I have just set an iomega Home Media Network Drive (Cloud Edition), and after updating firmware, it works smoothly with Moutain Lion so far. I am trying to set up access from outside my home network through internet, and there are few steps I am missing:

- DO i need to just enable remote access from the iomega menu (in my web browser access) or do i also need to enable port forwarding on the router too?

- The HD is hooked to an airport express for access when in the home network. Would it be recommend to plug it into the ISP router instead?

any suggestions on where to start?