hmm, good question! the way I do it is errr ... click the little quote button on one message I want to quote, then open the other message I want to quote in a new window, copy that code (eg [quote="name"]message ..... ) and paste it into my reply. Does that make sense?!
yes ... you see the little quote button at the top right of each post? right click THAT of the 2nd post you want to quote and choose 'open in a new window', copy that and paste it into the original window.