[Grml] grml-live, how to hold back packages

Hi,

How can I use a specific version of package (instead of the latest one) when building with grml-live?

Side question, current grml uses aufs-tools version 0+20090302, whereas the current aufs-tools version is 20100601-1. Is there anywhere I can find this aufs-tools version 0+20090302 that is used to build grml?

Thanks