After a plug-in configuration file is regenerated, it needs to be propagated to the Web server. The configuration service can automatically propagate the plugin-cfg.xml file to a Web server machine if it is configured on a managed node, and to an IBM HTTP Server if it is configured on an unmanaged node. For other scenarios, you must manually copy the file to the Web server machines. You can manually propagate the file by copying it from the application server machine to the Web server machine, or you can do it from the administrative console.
I tried propagating the plugin-cfg.xml file manually using the WAS Admin console by selecting the server and clicking on Propageate Plug-in button
Important: The Web server binary plug-in module checks for a new configuration file every 60 seconds. You can wait for the plug-in to find the changes, or you can restart the Web sever to invoke the changes immediately