We have been seeing more and more SS freewheels where it seems that BRW don't have the tool to remove it. It turns out BRW doesn't have a tool because there isn't a tool. Some new Shimano freewheels and many others are non-removable.
Here is a Park Tool article on how to "destructively" remove these freewheels with pics of non-removable freewheels.
http://www.parktool.com/repair/readhowto.asp?id=46Main trick is that the freewheel cover is left hand threaded (CW to loosen, CCW to tighten).