Properties must be strings or numbers. A maximum of 20 properties are supported per event. Properties appear in the goal detail view in the dashboard once a matching goal is created.
Events are only counted in the dashboard when a matching Custom event goal exists. Create a goal with the same event name in Settings > Goals to start seeing completions and conversion rates.
If you need to fire an event from your server (for example, after a payment is confirmed server-side), use the Events API instead of the JavaScript API. See Server-side tracking for details.