It seemed to me that it works, adding this towards the end of my TFSBuild.proj
<Target Name="PackageBinaries">
<ItemGroup>
<FilesToDrop Include="$(SolutionRoot)\MyProduct\Installer\Bin\**\*.msi"/>
</ItemGroup>
<Message Text="FilesToDrop=@(FilesToDrop)"/>
<Copy SourceFiles="@(FilesToDrop)"
DestinationFiles="@(FilesToDrop ->'$(BinariesRoot)\%(RecursiveDir)%(Filename)%(Extension)')"/>
</Target>
msi Binaries, tfs, . , Binaries , .
PackageBinaries - , .
TFS, , !