Fossil SCM

C:\>mkdir foo && cd foo

C:\foo>fossil new foo.fossil -A user && fossil open foo.fossil
project-id: 5c85d18244ac61ce53663aaf9564ba425778ab05
server-id:  7bf3921ae4405e639e511472090335b9b74518a2
admin-user: user (initial password is "5e9829")

C:\foo>echo 1 > foo.txt

C:\foo>fossil add foo.txt
ADDED  foo.txt

C:\foo>fossil ci -m "1"
New_Version: bb7214199269a72bc45a44a02d8e7c4969540687

C:\foo>echo 2 > foo.txt

C:\foo>fossil close -f

C:\foo>fossil open foo.fossil
foo.txt
project-name: <unnamed>
repository:   C:/foo/foo.fossil
local-root:   C:/foo/
user-home:    C:/Documents and Settings/user/Application Data
project-code: 5c85d18244ac61ce53663aaf9564ba425778ab05
server-code:  7bf3921ae4405e639e511472090335b9b74518a2
checkout:     bb7214199269a72bc45a44a02d8e7c4969540687 2011-04-14 15:24:21 UTC
parent:       700370b105b7705eddc4444ac10e7ade904fd9d1 2011-04-14 15:23:58 UTC
child:        609b955cbbb03e0826167ef193b3c36d69c71646 2011-04-14 15:24:38 UTC
tags:         trunk
comment:      1 (user: user)

C:\foo>type foo.txt
1

C:\foo>fossil ver
This is fossil version [047e06193b] 2011-04-13 12:05:18 UTC

I know that there's a --keep option. But is there a setting which would force a fossil to always ask when overwriting my files? (I have a fossil repository on a flash drive, a drive letter is different on different machines so I need to close a repository on my machine before using it on other machine).