You might want to check this site
http://definitions.symantec.com/defs/update.txt
the section XVI
"XVI. Installing Virus Definition Files Manually
=====================================================================
If you do not want Intelligent Updater to install the new virus
definitions for you automatically, you can use the /DUMP command to
extract the virus definition files, then copy the appropriate files
to the virus definitions folder.
Installing Virus Definition Files Manually
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1. Copy the Intelligent Updater program (yyyymmdd-vvv-I32.EXE or
yyyymmdd-vvv-X86.EXE) to an empty, temporary folder.
2. Launch the Intelligent Updater program using the /DUMP command.
For the yyyymmdd-vvv-X86.EXE file, use the /EXTRACT command.
This will extract all the virus definitions to the folder. For
example, type yyyymmdd-vvv-I32.EXE /DUMP to extract the files. Or
type yyyymmdd-vvv-X86.EXE /EXTRACT [path] where path represents
the current directory. The yyyymmdd represents the date of the
definition set. The vvv represents the version number. For example,
the filename could be 20021231-001-I32.EXE for a December 31
definition set.
3. Copy the files to the virus definition folder. Copy the files to
this location:
C:\Program Files\Common Files\Symantec Shared\VirusDefs\Incoming\
NOTE: Copy the file ZDONE.DAT last. This file signals Norton
AntiVirus that the definition set has been completely loaded. If
it is not loaded last, it may cause errors."