I want to utilise my ephemeral storage as mentioned in this question but I seem to be falling at the first hurdle. I can't even see /mnt:

~$ df -ah
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1      8.0G  855M  6.8G  12% /
proc               0     0     0    - /proc
sysfs              0     0     0    - /sys
none               0     0     0    - /sys/fs/fuse/connections
none               0     0     0    - /sys/kernel/debug
none               0     0     0    - /sys/kernel/security
udev            288M  8.0K  288M   1% /dev
devpts             0     0     0    - /dev/pts
tmpfs           119M  152K  118M   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            296M     0  296M   0% /run/shm

This is from a vanilla instance of an ubuntu AMI (12.04-amd64-server-20120424 ami-a29943cb)

I'm not bothered about resizing the partition, I just want to be able to use the space for writing temp files.