As of the date this article was approved (October 2013), Smarts IP does not have the capability to handle and resolve NAT addresses. The current/latest Smarts IP Manager version automatically discovers any IP device running an SNMP agent in the whole network accessible to it. It does not currently have the capability to create translation tables internally working with the NAT devices (manually configured or automatic) to be able to do selective device discovery and monitoring.
If you would like have this feature added to Smarts IP Manager, you can submit an Enhancement Request.