You may need to purchase a generic foot in order to make the modification. Seems that some feet that come with some machines are too tall to work well with FMQ. Your Brother most likely takes short shank feet.
These threads might help with more info:
http://www.quiltingboard.com/main-f1...0-t153565.html
http://www.quiltingboard.com/main-f1...0-t153565.html