yes, we are indeed talking about the same thing
HAVING webmin installed is one thing -- what i meant to say is that if you actually USE webmin to set up SMB / other partitions and check off the box marked 'allow users to mount this partition', these mounts should show up in GNOME's 'Computer' the next time you log in.
again, i'm mentioning webmin because it's relatively simple, reliable, and works pretty much the same across different distributions. there are many other tools that can do the job as well.
if you want to get into the nitty-gritty of things, you could directly edit your /etc/fstab file and make sure the 'user' flag is mentioned on the given partition(s), but i'm not 100% sure that this is all that GNOME needs.
the other thing you should make sure of is that your user account has at least read access to the partition/mount in question.