No idea, for your info, these devices run a strip version of Debian Lenny. So you can do some research to see if there is an answer for your question.
What I know is… someonme already has a package for OpenVPN, see these pages.
http://www.highlevelbits.fr/index.php?option=com_content&view=article&id=605&Itemid=80&lang=fr
http://mybookworld.wikidot.com/mybook-live
And last, the easier solution would be SSH access remotely, which would allow you to SCP/SFTP. It all depends on your needs