Is the WCF web service hosted in IIS? Does the WCF service use the configuration from web.config?
What if you change your WCF logging configuration to use a different trace listener to see if logging is occuring? For testing you could try using Event Log Trace Listener using Application log and "Application" as the event source name (that should
hopefully avoid any permission problems since those registry keys should already be configured). If the message is logged by the WCF service in the Event Log then it would look like the issue might be some sort of permission or networking issue since
the Email Trace Listener settings were validated when sending an email with the the test client.
Enterprise Library support engineer