I learned today that the TRACE verb is typically turned off at a webserver.

No wonder I could not get it to do much here. This suggests you must explictly turn TRACE on at Web.config to get it to work in an ASP.NET application. It's example is:

<configuration>
   <system.web>
      <trace enabled="true" pageOutput="false" requestLimit="40" localOnly="false"/>
   </system.web>
</configuration>