warning: kinda long post!
 
my SO and i have 3 ferrets.  we have 2 carry sacks of the type you
described, and they love them.  our ferrets don't like unnecessary
confinement, so we trained them sorta the same way we trained them
to think of the carriers as good things.
 
first, we put the carry sacks on the floor, and let them investigate.
they got in and sniffed, hopped on top and sniffed, got underneath and
sniffed.  we let them do that until they were bored or tired and went
away.
 
then, we put little bits of kibble inside, and left them out with them for
about a week.  we've found that with the carriers, and then with the carry
sacks, when we leave them around, the ferrets think of them as stuff they
play with or use every day, so they aren't intimidated by them.  by the
end of 3 days, we'd find them sleeping in the carry sack, and stashing
food in there.
 
once they were comfy with them, we put them in their harnesses.  for
them, harnesses mean going out.  usually, if we harness them up and put
a carrier near them, they just snuggle inside and wait for us to be ready
to go.  so we harness them up, and put them in the carry sack while we're
wearing it without shutting it.  this part was a gradual process, so we
had to do it for several days, letting them feel like they could climb
out and not be trapped.  IMPORTANT: please don't ever force them to stay
in the carry sack if it's stressing them out.  they'll never like the
carry sack that way.
 
when they seemed not freaked out by it, we shut the zipper.  every time,
they'd go for longer and longer without complaining to come out.  the
whole process took somewhere around 2 weeks.  for some ferrets, it may be
shorter.
 
now they only complain to come out when they need a box, or if their
hungry or thirsty.  or, if they really wanna dig in some dirt or
something.  but even then, they just scratch a few times near the zipper
to signal they want out.  we still leave at least one sack out in the
room, so they can always be comfy in it. :)
 
hope this helps!
 
andrea and a somerville business
tiki, lucy and gabriel
 
*~*~*~*             *~*~*~*           *~*~*~*
 
"and every step of the way your mood brightens
so keep on goin' now, don't be frightened"
 
     "horizon" by ashby
     from the album _power ballads_
 
*~*~*~*             *~*~*~*           *~*~*~*
[Posted in FML issue 3703]