Get the Imperial Assault Campaign module for Vassal from http://www.vassalengine.org/wiki/Module:Star_Wars:_Imperial_Assault
The next total solar eclipse holiday in 2017 in the USA.
Re: Entire set of SWIA listed as not available on FFG website
It is constant. It means nothing.
Due to Hasbro having the Star Wars boardgame license in the US/NA, and the agreement between Hasbro and FFG, FFG cannot sell Imperial Assault online themselves. (FFG can sell it on their physical store.)
Everything except what you see in the Upcoming page is still available.