copy-to-dir fail with "file exists" not overridable

[BlauerHunger]

I'm trying to use acbuild to create an image for an application which uses config files in /etc. But when I try to import all the config from a directory on the local filesystem (let's call it image-data.d) (this directory contains a hierarchy such as /etc/apache2/apache2.conf /etc/apache2/sites-available/000-default.conf) with "acbuild copy-to-dir image-data.d/* /" I get an error "copy-to-dir: mkdir /.acbuild/currentaci/rootfs/etc: file exists" and the files don't get imported.
I don't want to specify each file to be imported because the build scripts I use should be as universal as possible.

Is there a way to make acbuild override existing files? (use cp -rf and mkdir -p)