Impulse wasn't showing Elemental as installed for you? Did you install Elemental through Impulse or from the dvd?
It was showing it as installed and in the current version. I've been using Impulse since the first Gal Civ version and from my experience everything looked exactly as it should, except for the download size. In the bottom of the screen it showed something like "Version: Version 1.10(1.11 update available).
I have installed digitally. In case it makes a difference, I haven't actually played the game since September, I just like to keep all my games updated so I don't have to start downloading when I feel the urge to play.