From my observation, I think drive letter access only works on a local LAN with the desktop software. Therefore, the computer you are on would have to see both drives on the same LAN, so I don't think that will work by itself.

Thinking outside the box though, you might be able to do it by creating a VPN to the remote network where the remote unit is seen as local by the software.

By the way, I have a dockstar and a pogoplug pro too. I have both registered in the my.pogoplug account and bypassed opening a second account on seagate.pogoplug.com. I can see all drives on both units in the same interface, which might allow you to do what you want without the drive letter access if you just want access to everything in one browser window. To combine them, I think you would need to unregister the dockstar at the seagate subdomain before adding it to regular pogoplug account.

I learned something new. I thought the desktop app only worked on the LAN. I'll have to install that at work this week now.

I have both pogoplug devices in my same account, so I see a drive letter for the drive attached to each one. I have one drive on my dockstar near my computer which is drive W, and two drives on my pogoplug which is downstairs which show drives X and Y. All three drives appear in windows explorer or powerdesk and I can drag and drop between any of them. I think if you move your dockstar to your my.pogoplug account under a single login you'll see them consolidated.

I am using the Pogoplug Pro at home and a Dockstar at work. I used the same email address/password to register both devices, and they both show up on my local computer as a local drive, when running the Pogoplug Drive software. It works great!