@MainEndPointUser: As what everybody else have said. The actual respolsibility lies with your security vendor. It is their responsibility to keep your IT security systems in check. All software providers (Windows, Symantec, etc...) always recommend to have your system up-to-date with the latest patches. And based from personal experience - SAV 10 onwards do detect threats as long as the definitions are updated.
Vendors usually are members of PartnetNet, both the client and the vendor can call Symantec when problems arise (e.g. They can be your first level of escalation which then in turn calls on Symantec for help.)
When the Symantec AV failed on your system, they should have made some fixes. There are a lot of solutions available in the KB that they could've implemented.
Our company does deployments and when we fail - we keep on trying. :D
Glad you have resolved the issue. And may I suggest for your team to have a discussion with them on the following topics:
1. Deployment and update plan - both for software and definitions.
2. Disaster recovery plan - both for system failure and outbreak.
3. System monitoring.
Cheers.