如何使Mono的Xbuild中的msbuild任务使用.NET 3.5框架?

我正在尝试使用Xbuild(显然是在Mac上)构建一个单触式项目。这是我的Xbuild项目:

<Project DefaultTargets="Application" ToolsVersion="3.5" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <ApplicationProjectFilePath>..\TestApp\TestApp.csproj</ApplicationProjectFilePath>    
        <TargetFrameworkVersion>v3.5</TargetFrameworkVersion>
        <MonoTouchReferencePath>/Developer/MonoTouch/usr/lib/mono/2.1/</MonoTouchReferencePath>
    </PropertyGroup>

    <Target Name="Application">
        <MSBuild Projects="$(ApplicationProjectFilePath)" Targets="Rebuild" Properties="Configuration=AdHoc;Platform=iPhone;ReferencePath=$(MonoTouchReferencePath)" ToolsVersion="3.5"/>
    </Target>
</Project>

当我运行此命令时,会收到以下警告:

/Library/Frameworks/Mono.framework/Versions/2.6.7/lib/mono/3.5/Microsoft.Common.targets:  warning : Found a conflict between : 'System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' and 'System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. Using 'System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' reference.

如何让Xbuild引用v3.5框架?正如你从剧本中看到的,我试过很多方法,但似乎都不管用。

[另外,我不知道为什么我必须显式地引用monotouch.dll库-因为它在项目文件(testapp.csproj)中被引用。对此的任何评论也将不胜感激。]