I'm transitioning a basic oldest -> newest comment system to a threaded system. The new system will allow for a single level of depth and the threads will be sorted by newest -> oldest. Under each parent comment will be a list of replies from oldest -> newest. This is much like the way Facebook handles status updates.
What I'd like to know is how to smoothly transition my users. Currently they go to the bottom of a page to post a new comment, but now they will need to go to the middle of the page (or the top of the comments) to post a new thread.
I was considering adding an anchor button at the bottom of the threads to bring the user to the middle of the page to start a new thread.
Are there any considerations I'm missing in this transition?