Question about Stealth Armor

[Maerlyn]

Hi guys, I am a Space empires newbie and am just enjoing my first PBW game, and its GREAT but besides that I am still encountering some troubles.

so here it goes: as far as the manual says the stealth armor should prevent me from seeing an enemyship equiped with it, because all my ships (I dont got any sensor except for combat sensors at the moment) can only do active EM scans lvl 1.
is this true?
and if this is true, why to hell can I still see his stealth armor ships?
I am not using any longrange scanners nor have a got any patnerships.

thanx for answering this
have fun
maerlyn