That is the whole idea of jail breaking: the ability to edit files on the disc that are owned by
root. Either you jailbreak the iPad and you can edit the files in /var directly or you can not.
Unless you find out the root password ;)
Regarding the link in comment.
There are 3 situations:
The software you get when you buy Apple products.
3rd party software that replaces the software Apple put on the device and enhance the current features. These use the permissions and or directories that are already open on the device. This includes (but is not limited to) tethering (browsing over the iPad; basically this is telling the kernel to use a module), adding music or pictures, manage installed applications, synch addressbook/calendars/notes and bookmarks. These things can be added without having root access. They add files to userspace.
Software Apple does not want you to install on the device. These are for instance rootkits, ssh and/or telnet connections. These require you to jailbreak so you can become the root user of the device.
The partition where /var/ is located is most likely mounted as Read Only (heck you can even assume that the whole system is mounted Read Only and only the user partition is Read/Write). To change this you need to jailbreak: then you can umount the partition, remount it as read-write and change content to it. Any Apple product that is capable of writing to /var/ (if they even make this possible) is more than likely going to do something similar: remount the partition to read-write , write the files and remount read-only whilst making sure along the way it is done with untampered software Apple wrote.