I made the following entry within capsd-configuration:

<protocol-plugin protocol="NSClient" class-name="org.opennms.netmgt.capsd.plugins.NsclientPlugin" scan="on" user-defined="false">
<property key="banner" value="*" />
<property key="port" value="1248" />
<property key="timeout" value="3000" />
<property key="retry" value="2" />
</protocol-plugin>

Had OpenNMS discover a host with the NSClient loaded, the service was detected and added to the UI as 'not discovered. (everything is fine thus far)

However, if I go into Admin --> Configure Pollers --> Add Customer Poller and click 'Cancel'... all of the NSClient information (from above) is erased from capsd-configuration... or, it actually appears as if capsd-configuration is being overwritten with the default file.

It's odd, but despite the entry being removed from capsd-config, OpenNMS does continue to scan for this service, on this node, when rescanned.

I hope that made sense . I had this conversation on IM with joed.