Equipment for missions?

Im confused cuzz I passed a mission will the silent assassian rating and it says I earned a new gun but then I start the next mission and the game doesnt give me the chance to select a new weapon for the mission ahead. The only way I can use the weapons I earned is to use them in trainning and thats it. Am I missing something or are we not allowed to equip the guns we earned for the next mission?

[FredtheHobo]

the first time round on each mission you get a standard loadout. after you've beaten the game you can go back and play each mission with whatever guns you want.

So how would I equip weapons for missions when playing the game for the second time?

just quit the game when youve unlocked the guns, then choose a level wgich you have already completed, then it'll come up with the equipment screen