My virtual drives and one physical drive show blank labels when Drive Icons in the Drive Toolbar are moused over. Other drives show the same labels as in the Folder Tree and File Pane. All drives show their labels in the Folder Tree and File Pane.
examples:
Blank Label as displayed mousing over Drive Toolbar drive icon- "B:"
Name as displayed in Folder Tree and File Pane - "Home Docs (B:)"
I applied the following registry entries to create virtual drives that are persistent across PC restarts following the procedures found here - http://en.wikipedia.org/wiki/Subst#Custom_label
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\DOS Devices]
"L:"="\??\D:\Lab"
"B:"="\??\D:\Home"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons\B]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons\B\DefaultLabel]
@="Home Docs"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons\L]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons\L\DefaultLabel]
@="Lab Docs"
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons\D]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons\D\DefaultLabel]
@="Doc"