automatic package upload

I have just read Gregory Beaver's PEAR Installer Manifesto and am attempting to setup a PEAR channel for the open source project where I contribute: http://code.google.com/p/qubit-toolkit/ We would like to automatically upload nightly snapshots to our PEAR channel, but I haven't found any documentation about automatic uploads. Is there a anything like a "pear upload" command? We installed Chiara_PEAR_Server, which supports manually uploading packages through a web interface. Is there a convenient way to do this automatically? Possibly using the package's GPG signature for authentication? Alternatively, we could upload packages to the server using SSH, and our SSH keys for authentication. Is there a PHP script we could run on the server, to load the package into Chiara_PEAR_Server? Thanks and best wishes, Jack