you have to click the multi-quote button on each post you want to quote, then click quote on one of them and it'll automatically add them to the reply box. is that what you were doing?
"What, exactly, is the internet? Basically it is a global network exchanging digitized data in such a way that any computer, anywhere, that is equipped with a device called a 'modem', can make a noise like a duck choking on a kazoo." - Dave Barry