USMT 3 : Migrating Printers and Network drives
From the archive (2009). Written for the tools of the time, so some details may be out of date.
USMT version 3, no longer migrates printers in Windows XP by default. USMT 2.6 did do this type of migration. In order to migrate printer and network drives, you need to create a custom.xml file.
Here is an example of the information you need. Remember that your http line needs to contain the filename at the end, so in this case the file would be custom.xml
<migration urlid=http://www.microsoft.com/migration/1.0/migxmlext/custom>
(make sure to change { to [, } to ] formatting issue)