I must say that the first time I met a 12 years old stone boy armed with an RPG, I almost pee on me. I was protected only by a piece of paper from his chief... That wasn't much.
I do agree that killing children, women... is not to be done. But as said some COS I met in Bunia: a 12 years old boy with a gun is may be a 12 years old boy but it is also a guy with a gun and less aware of what he is doing than an adult. Well not really if both are under drugs.

But you pointed out all the difficulty to have a civilian oriented war or even instrumentalisation of humanitarian aid. Abu Suleyman was stating: "who you help is the important issue, not the structure of the conflict." Well if you do not help starving under 5 children then you have a problem, cause at the end, you end up in practicing, even indirectly, violence on innocent civilians. Kids can barelly being charged for their parents choices, not talking about women in contexts as Afghanistan. On the otherhand, your feeding you enemi.

"I have to say I am pretty cynical about any construct of a "Just War", especially one that is largely the product of European Culture." (William F. Owen)
"My view is that ends and methods are both necessary but not sufficient conditions of justification. Any attempt to define a war as just without looking at both of them will result in a lot of tail chasing." (Abu Suleyman)

What is interresting from your and Abu Suleyman comments is that it seems like there is a cultural interpretation of "Just war". North Americans would have a different view on Just war compare to europeans.
Also, the actual concept of just war (based on proportionality, response to an agression...) is a US concept brought by M. Walzer. It was a critic of US way to conduct war in Viet Nam. (on this, it's not me, it's you)Would that mean that US army is having a double look at it ? Assimetric war would justify an disproportionated response or would that just be missing the point in such confrontation?