Junio C Hamano wrote:
>  * transport-helper, fast-import and fast-export have been updated to
>    allow the ref mapping and ref deletion in a way similar to the
>    natively supported transports.

Have they?

% git --version
git version 2.0.0.rc0
% git push origin origin master:foo                                                                                /tmp/test[master] nysa
searching for changes
no changes found
fatal: remote-helpers do not support old:new syntax
ERROR: unhandled export command:

I think you are missing the patches which I just resent[1].

[1] http://article.gmane.org/gmane.comp.version-control.git/246558

-- 
Felipe Contreras