hg convert misses files

[Raymond Toy]

I'm tryin to extract a directory from an hg repo and create a new repo
from it.  I followed the basic info from
http://mercurial.selenic.com/wiki/ConvertExtension, and use

hg convert --filemap /tmp/map /path/to/repo/subdir /tmp/subdir-repo

where /tmp/map contains

  include subdir
  rename subdir .

It looks like the conversion succeeds.  But when I look at the new
repo, it's missing many files.

What am I doing wrong with the conversion?  I'd like to keep all the
history in the new repo.

BTW, I'm using hg 1.7.2 running on OSX.

Ray