Hello David,
If WDA = Web Dynpro ABAP, then please refer below links:
Launching Web Dynpro applications through CRM Web UI - CRM - SCN Wiki
Different UI Behaviors: ABAP Webdynpro Vs CRM Webclient UI - CRM - SCN Wiki
Issue lists of using ABAP Webdynpro in CRM UI
Configure ABAP webdynpro component into CRM system via Transaction launcher - CRM - SCN Wiki
Integrating web dynpro application into CRM WEB... | SCN
Thanks,
Kapil