I'm trying to set the OutputPath value to an absolute path:

<OutputPath>c:\Projects\xxx\Deployment</OutputPath>

But I get this error:

Error   17  The expression "[System.IO.Path]::GetFullPath(D:\Projects\xxx\trunk\xxx.Web.Deployment\c:\Projects\xxx\Deployment\)" cannot be evaluated. The given path's format is not supported.     1   1   xxx.Web.Deployment

Is there a way to use an absolute path with the OutputPath property? I've tried experimenting with the BaseOutputPath property:

<PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Deployment|AnyCPU'">
  <BaseOutputPath>C:\Projects\xxx\</BaseOutputPath>
  <OutputPath>.\Deployment</OutputPath>
  <EnableUpdateable>true</EnableUpdateable>
  <UseMerge>true</UseMerge>
  <SingleAssemblyName>xxx.Web.Deployment</SingleAssemblyName>

But it seems to get ignored. What are BaseOutputPath and BaseIntermediateOutputPath used for?