Unable to resolve FSharpTargetsPath on machines with VS2013

I have a solution with an F# portable class library. The solution builds fine using Visual Studio 2013 (I don't have earlier VS versions, that the only one on that machine). When I try to build the solution using Xamarin Studio, the F# fails without giving a sensible error message. I had to build the solution from a command line using mdtool in order find out what the error was.

And the error was caused by this section:

  <Choose>
    <When Condition="'$(VisualStudioVersion)' == '11.0'">
      <PropertyGroup>
        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.Portable.FSharp.Targets</FSharpTargetsPath>
      </PropertyGroup>
    </When>
    <Otherwise>
      <PropertyGroup>
        <FSharpTargetsPath>$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\FSharp\Microsoft.Portable.FSharp.Targets</FSharpTargetsPath>
      </PropertyGroup>
    </Otherwise>
  </Choose>

When I hard-coded the value of FSharpTargetPath property and pointed it to the path of the F# targets file, everything worked fine. But of course this should be solved properly, so I wonder what's the best way to fix this problem.

Or should I submit a bug report?

Thanks in advance Vagif