NVDA 2015.2 is here,  and it works with the Acapela TTS for NVDA right away! So just update NVDA and go on working with your Acapela voice with no need for any operation on your side.

You can download NVDA 2015.2 here:

http://www.nvaccess.org/post/nvda-2015-2-now-available/

Enjoy it!