git archive --worktree-attributes doesn't exclude .gitattributes anymore

git version 1.8.1.2 (please cc me, I'm not subscribed to this list)

Hi Developers, I write here because since my ubuntu update (quantal to raring) and git update from 1.7.10.4-1ubuntu1 to 1.8.1.2

my export script doesn't work anymore.

I tried to put .gitattributes or .git/info/attributes, the file is the following http://pastebin.com/irngA1L8

the git is git clone http://boinc.berkeley.edu/git/boinc-v2.git

and the command is

git archive --prefix boinc-7.1.7+dfsg/ --format tgz -o ../boinc_7.1.7+dfsg.orig.tar.gz -9  client_release/7.1/7.1.7

The archive gets created, but every file is inside, no exclusions at all.

I suspect a regression between git 1.7 and 1.8

thanks for your time

Gianfranco