Step down rings have a female thread which allows you to to screw items in from both sides and hence use it as a female to female adapter. The problem would be to get a step down ring which is large enough to allow the filter to fit inside the male threaded part. Something like a 105-77 might be large enough if you can find one. Alternatively 82-77 is readily available but you would need to remove the 82mm male thread (with a small hacksaw?) leaving you with just a female 77mm ring.