Hi Igal,
If your switch is not showing up, there could be a few different causes. To troubleshoot:
1. Check the configuration of the Sensor
Nodes can be manually imported via API or through use of the Web Console. Pre-registering a node or device before it is detected can allow you to assign policy ahead of time, however, until the switch is detected by the sensor scan or snmp, visibility (detection of the switch and port mapping), and enforcement (arp enforcement, snmp port shutdown, etc.) against the switch itself is not possible.