I am running virtualbox 4.2.4 r81684 on an ubuntu 12.10 installation with cinnamon desktop I have just installed ubuntu 12.10 server in virtual box and I have guest additions installed virtualbox was installed using these instructions http://www.liberiangeek.net/2012/09/install-virtualbox-4-2-via-its-repository-in-ubuntu-12-04/
I have bi directional set under shared clipboard and there is a grey tick next to VBoxGuestAdditions.iso when I check the devices
So why is it that when I copy text from my host can I not paste it into my guest? If I use CTRL+v on the command line of Ubuntu Server (guest) I get nothing and if I CTRL+v a second time I just get ASCII characters.
I get the same problem if I use Shift+Insert
Update
Session information shows that guest additions is not detected

Runtime Attributes
Screen Resolution
640x480x32
Clipboard Mode
Bidirectional
Drag'n'Drop Mode
Bidirectional
VT-x/AMD-V
Enabled
Nested Paging
Enabled
Guest Additions
Not Detected
Guest OS Type
Ubuntu (64 bit)
Remote Desktop Server Port
Not Available

Storage Statistics
Controller: IDE Controller
IDE Secondary Master:
DMA Transfers
16
PIO Transfers
534
Data Read
49,152 B
Data Written
0 B
Controller: SATA Controller
SATA Port 0:
DMA Transfers
6,606
Data Read
159,972,352 B
Data Written
3,717,120 B

Network Statistics
Adapter 1
Data Transmitted
2,170 B
Data Received
16,977 B