As said it's possible, it takes a bit of time but in reality not that much if really want the quote.
1) Copy paste the post
2) Place it between quoting tags
3) In the first tag, after quote, add the symbol '=', then the member's name, the ";" symbol and lastly the number of the post. The Brown Guy already gave the visual coding for it.
4) The number of the post can be found in the URL link of that post, which in return can be found by clicking on the specific number of that post in the thread that's located on the black bar above the post on the right.
It's not really that much effort as the URL link of a post, the member who posted it and the post itself are all located in the same place. You only need to combine them. It's not so much different than coding your regular posts.