Also, Procrustes, it has been pointed out that while quite odd and incomprehensible to me, the following fact stands:
it is far more likely for your generals to get VnV's after a battle if you autocalc.
you may have half a dozen battles and not gain one virtue, but just do an autocalc and you'll see what I mean.

I suppose these are all bugs, because I for one can't see the point.
It's the same with capturing generals/princes/kings: try to do it manually, and half the time you may end up killing them; autocalc, and you'll ALWAYS capture them (thanks to katank for pointing it out a long time ago).

Also, if you look up some building-jedi-directions threads, you'll notice there are quite a few lines of VnV's that you can acquire for sure for your general. The thing is, that's perfectly true, but ONLY if you autocalc. I tried it myself several times and unfortunately that's the way it works.