[arch-general] grml-zsh-config and VCS_info

I'd know if there's a way to resolve the following issue: I use grml-zsh-config, but the VCS_info prompt inside a Mercurial repository doesn't work. The strange thing is that VCS_info prompt correctly works for git and bazaar (as you can see at <http://img256.imageshack.us/img256/6088/immagineqd.jpg>). I haven't modified anything in the /etc/zsh/zshrc. Does anybody know a solution? TIA