I am not entirely familiar with the OpenSUSE distro, but your step 6 seems a bit much. Most modern linux distros can simply install the DKMS package, and then run the installer script from the .iso.

I am wondering if perhaps the guest additions aren't fully integrated - and they don't get activated early enough in the boot process to allow your entry in fstab to actually get recognized.

I am not entirely familiar with the openSUSE distro, but your step 6 seems a bit much. Most modern linux distros can simply install the DKMS package, and then run the installer script from the .iso.

I am wondering if perhaps the guest additions aren't fully integrated - and they don't get activated early enough in the boot process to allow your entry in fstab to actually get recognized.

Update: I downloaded and installed openSUSE-11.3-GNOME-LiveCD-i686.iso, and the installer detected I was in VirtualBox and automatically started the Guest Additions. Also, once it had finished and booted to the desktop the Guest Additions were automatically started for me as well. There was nothing I needed to install - though I didn't test the auto-mounting once I was puzzled by the auto install of the additions.

Your question indicates you are using version 11.3, the instructions you copied and pasted indicate 11.2... What version of openSUSE distro are you testing? It is also the guest correct? What is your host OS? What version of VirtualBox are you running?