ePO will not actually do an uninstall of a another vendors product. VSE is the application that will do the uninstall. The VSE program has an uninstall.ini that contains all the products that it is able to remove. I would test on a local machine first by trying to install the VSE application. I would also recommend if the SEP program has any protection feature from the software being uninstalled please disable it. This could be a password or registry key etc.
If you are using SEP Sygate versions which includes the device control/firewall part,its not going to be removed by deploying Virusscan 8.7 patch2.You can however procure uninstall utility from Symantec for their SEP product which can help in overriding any security mechanisms that you might have.
However take specific attention that the tools they provide are not supported and are found to crash the PC while uninstalling SEP from the endpoints.