[vile] I can't get 'fillcol' to work

[cl]

I'm using a wide window but want to stay within 80 columns
when I'm in mutt.

So I have added a 'set fillcol=70' when using vile from mutt (my
mail program).  The value is certainly set, it appears when I do a
'setall' but it seems to be having no effect.  I have, in addition,
tried unsetting 'wrapmargin' but with 'fillcol' set to 70 and 
'wrapmargin' unset I get no autowrap at all.

Am I misunderstanding what fillcol is supposed to do or is it broken?

-- 
Chris Green (address@hidden)