Service Writing Log Files With My.Application.Log To Wrong Folder

I have written a VB.NET (2005) service that is using My.Application.Log to write log entries to a FileLogTraceListener. I have configured the Listener in app.config to write the log file to the executable file's directory by using

location="ExecutableDirectory"

When the service runs, it writes log entries just fine, but they are not in the executable file's folder, but rather in Documents and SettingsLocalServiceApplicationData....1.0.0.0mylog.log

Why is the location parameter not being honored?

Here is the complete system.diagnostics section from my app.config.

<system.diagnostics>
<sources>
<!-- This section defines the logging configuration for My.Application.Log -->
<source name="SplintService" switchName="DefaultSwitch">

[Code].....