I use BYOBU myself in the same manner. I just use cygwin these days (F2as F2,3,4 and F6 just work for me, and those are the only ones i'mI'm really concerned about). However, butwhen I remember having to change some keyboard settings inwas using putty way back when. The exact details escape me right now, if I have a chance after work I'll try it outhad the most success with 'The Function keys and update here.keypad' setting set to emulate VT100+