Hello:
I think this is a question for CUAE developer forum.
This article may answer your questions:
http://developer.cisco.com/web/cdc/wikidocs?src=/wiki/display/CUAE/Example+-+CatPluginBasically, your plugin is going to be the middle-ware which consumes WSDL exposed by Wireless Location Appliance and then your plugin exposes Etch IDL for other Etch clients to consume.
Please post any further question about this topic in CUAE developer forum.
Thanks!