Its pretty simple, but it took me forever to figure out how to do it.
You just need to alter the masterTEXTFILE located in "Program Files\LucasArts\Star Wars Empire at War\GameData\Data\Text." Its a .dat file so you will need a dat editor. You can find one here-
http://pff.swrebellion.com/index.php?topic=2663.0)
To find out what line you need to change, look at the the line <Encyclopedia_Text> **** </Encyclopedia_Text> in the appropriate XML. For example, Home One would be <Encyclopedia_Text> TEXT_TOOLTIP_HOME_ONE </Encyclopedia_Text>.
Just FYI, the unit name is <Text_ID>TEXT_UNIT_HOME_ONE</Text_ID>.
EDIT: DOH! Seems mandead beat me to it.