Thanks for the starting point.
I understand very little on port forwarding and it doesn't "sound" like it's the most efficient way to solve the problem (i.e. why use a software workaround when we just want the router to "see" the drive and "talk" to it directly?).
If it helps, the router I'm using is the Actiontec MI424WR Rev. 1.
If the port forwarding explained in the link IS the best option, if you could explain or point me to a link that might explain how and why it's done, it'd be appreciated. Some routers have no problem with this network drive enclosure and some refuse to acknowledge its existence and this seems to be one of the latter, unfortunately. Maybe it owes the Actiontec money. ;-)