vBulletin amendments

I have a vBulletin forum on my website. Effectively, this forum has just one single thread into which people can post their own comments and also reply to any comments there are. Initially, I want to change the text of some of the existing buttons. For instance, I want the "Reply with quotes" button at the bottom of each post in a thread to just say "Reply" - so that all replies quote the original post. And I want the existing "Reply" button to say "Add your own post" and I want to put in an "Add your own post" button to the top and bottom of the thread.