One of the new tasks available in Team Build Orcas (VS 2008) is the SetBuildProperties task.  This task allows you to modify any of the settable properties of a BuildDetail object directly from you MSBuild script (TfsBuild.proj).  The settable properties include:

• BuildNumber.  This is often displayed in the GUI as Build Name.
• CompilationStatus.  A string representation of the BuildPhaseStatus value for the compilation phase of the build.  Valid values include "Failed", "Succeeded", and "Unknown".
• DropLocation.  The location of the build outputs - typically a UNC path.
• LabelName.  The name of the version control label generated for the build.
• LogLocation.  The location of the log file for the build - typically a file called BuildLog.txt at the DropLocation.
• Quality.  The quality of the build.
• SourceGetVersion.  The version specifier used to retrieve source files for the build.
• Status.  A string representation of the BuildStatus value for the overall status of the build.  Valid values include "InProgress", "Succeeded", "PartiallySucceeded", "Failed", "Stopped", and "NotStarted".
• TestStatus.  A string representation of the BuildPhaseStatus value for the testing phase of the build.  Valid values include "Failed", "Succeeded", and "Unknown".

Using the task is pretty simple - just specify the TeamFoundationServerUrl and BuildUri that identify the BuildDetail to be modified and set the desired properties to their new values.  For example, to set the log location for a build to a URL, rather than the typical UNC path, you might do something like the following:

  <Target Name="AfterDropBuild">
    <SetBuildProperties TeamFoundationServerUrl="$(TeamFoundationServerUrl)"
                        BuildUri="$(BuildUri)"
                        LogLocation="http://www.myurl.com/BuildOutput/BuildNumber_20071016/BuildLog.htm" />
  </Target>

After this change, the link to the log file in the build report for this build will show the new URL, rather than the default UNC path.