Remember mana magic targets living auras.
It's a little abstract, but think of it this way. Putting on a suit of armor is making it a part of your essential 'me'-ness. Standing behind a piece of paper does not, nor does getting into a car. The spell targets your essential 'me'-ness, your living aura.
-k
If this is the case, why am I unable to wear a pair of glasses which are required by prescription and I've worn my entire life, and have a thermographic sensor in them, and use them to target someone with their thermal signature behind said sheet of paper? Yet I can do so same with a pair of Cybereyes I spent Essence on. Unless I'm mistaken, in which case I suppose I'm talking out of my ass. I'll go check that right now to make sure.
SPELLCASTING
Can you cast spells if blind?
Sight is the most common means of establishing a connection with a target (hence the range “Line of Sight”), but by no means the only one. If you physically see, astrally perceive, or touch the target, you can cast the spell.
In situations where the player wishes for their character to use another sense (hearing, smell, echolocation, etc.) to cast a spell, it’s up to the gamemaster to decide if that is possible. At the very least, a Perception Test involving the sense in question is called for, with appropriate modifiers (Using Perception, pp.135-136, SR4A). In the case of enhanced senses, the enhanced sense must be integral to the character (i.e., cyberears with audio enhancement would work, but earplugs with audio enhancement would not). Naturally, this works better for Indirect Combat Spells than others.
It would appear that yes, installing a Cyberware Scanner into a pair of Cybereyes/Ears/Whatever else and using it to spot someones cyberarm through a wall would infact allow you to target them through a wall. Yet that same sensore, even with a close personal attachment, cannot be done without Essence being paid.