Are you wanting the VA itself or the configuration of the appliance so you can restore to a new virtual system?
If the former, it should be done as any other VM; if the latter, export the system.cfg (Maintenance>Import/Export>System) for the certificates, licensing, logging, and other unique settings and the user.cfg (Maintenance>Import/Export>User Accounts) for the rest of the configuration (Users, Realms, Roles, ACLs, etc)