You need to use 'ePOPolicyMigration' tool to migrate the policies from VSE 8.7 to 8.8.
I recently used the tool hem mentioned, and it is packaged in the VirusScan download. Extract the files and run 'ePOPolicyMigration.exe' while logged into your EPO server. It worked very well for me.
you'll need to check in the extension for VSE8.8 before running the migration tool.
run migration tool on epo server
you may need to provide a password when running the tool, via command line. use "epopolicymigration.exe /?" for syntax if the tool fails.
process is described in installation guide for VSE.
tool will migrate policies, tasks, and policy and task assignments.