Fresh install of webmin on a redhat ( CentOS 5.5) trixbox phone server box. Under the Disk and network filesystems there is no drop down listing for a windows network share. I am not 100% new to Linux but am still learning the ins and outs of file system manegment.
Does your system have the mount.smb or mount.smbfs commands installed?
Without those, Webmin cannot mount SMB filesystems..