Create 64 bit
You have to create ("export") a 64-bit package, but it isn't difficult.
At the SEPM, go to Admin > Install Packages.
If required, create your own feature set and installation settings.
Then select Client Install Package and highlight the appropriate SEP client package in the right pane (e.g., "Symantec Endpoint Protection version 11.0.7101.xyz for WIN64BIT").
Now click on Tasks/Export a Client Install Package, determine the local folder for the package, enable "Create a single .exe file", choose the installation settings and the feature set, enable "Export a managed client" and choose the group the client shall enter.
Now press OK, and after some time the 64-bit package is created and stored in the folder you had specified. Now you can deploy this file remotely, or run it directly on the 64-bit client.