You need to add necessary poller to the node in order to get polled. You can find samples of adding poller to the node @ "C:\Projects\SWIS\M_SWIS\depot\Dev\Main\Orion\SDK\Src\Samples\PowerShell".
I see couple of pollers for ICMP. Add what is required for your purpose.
N.IPAddress.ICMP.Generic :: IP addresses poller for ICMP devices. Poller performs reverse/forward DNS lookup to gather IP addresses.
N.StatusAndResponseTime.ICMP.SendEcho :: Node response time and status poller which utilizes ICMP query to find out if node is responding. Poller utilize Win32 API IcmpSendEcho method to measure response time and node status.