How can I browse the hard disk attached to my Airport Extreme from my iPhone? I have a gen 5 AEBS which has a total of 3 HFS+ partitions across 2 USB hard drives (USB hub in the middle).

On my Macbook Pro Retina, I can see all 3 HFS+ partition in the Finder. Finder shows the AEBS on the left side (under "shared) and clicking on the AEBS in Finder shows me all the 3 HFS+ partitions "on" the AEBS.

In a similar manner, I want to access the AEBS USB hard drives from my iPhone 5 but I couldn't find an app for that. Does anyone know of an app or in-built way for me to access the drives attached to my AEBS? I'm looking for access when I'm on the AEBS WiFi but if I can also access it from the internet, that'll be a nice bonus!
Try FileExplorer Free from the AppStore.  I got my iPhone to see the files on a HD attached to my Airport Extreme Router.

The HD has to be formatted as HFS+ (Mac OS Extended Journaled)