[ESS] underscore in BUGS mode

[Jack Tanner]

Sorry if this is a FAQ; I searched in the archives but didn't find an answer.

1. In ESS[BUGS] mode, underscore is bound to ess-bugs-hot-arrow, which is
definitely wrong, because it doesn't let me create variables like foo_bar. 

2. I'd like it if I could use smart-underscore as in ESS[S] mode, but if I do

(define-key ess-bugs-mode-map (kbd "_") 'ess-smart-underscore)

then there's no smart-underscore behavior, just a plain underscore.