Maybe if you created/used a shp icon which represented an invisible unit.  If you can not see it, then it may be useful for your concept.  Unfortunately, I do not think that you can fool the computer/IA, as it will find it as a target even though it appears 'invisible'.  As written above, it needs at least one crew member.  Which may not give you the weapon you're seeking.  An example:  I once tried to create suicide bombers using infantry icons as ammo carriers armed with a bomb.  It didn't really work well, because the bomber either survived, or was 'born again' as a crew member!  Not very realistic.  Unless you believe in reincarnation.  You can also try creating a weapon similar to a 500lb (example) bomb with range.  Give it to an infantry unit.  IE:  armed with bomb with 3 range.  Only one bomb.  It could be neat. 
