Although the Intronis software cannot be installed on a Linux machine, you can share out those files and back them up from a compatible Windows machine.
The first thing you will need to do is share the files on the Linux machine via a UNC path. In order to share files with Windows computers, you will need to have Samba installed on the Linux machine. Nearly all distributions of Linux have Samba already included, but if you do not you can download it from here.
Once the files are shared out you will need to add them to a new or existing backup set. Instructions for backing up network shares are here.