It says when you disband a brigade that the remaining troops will go to 'the pool', but I can't work out what actually happens. They certainly don't seem to go back to their home province. For example, I just had 2000 irregulars from Buenos Aires, which only had 300 soldier pops left. After disbanding, it still only has 300 soldier pops. So where did the 2000 men in the brigade go?