Any suggestion for directory layout of project support both Full.NET Framework and Compact Framework?

Recently, i am busying myself on a project that support both the Full
..NET Framework 2.0 and .NET Compact Framework 2.0, with the same set of
c# code, but have different project properties and references.

The question is how could I achieve this, should i create separate
project for each purpose?

The most simple approach is creating two separate projects, but i'll
must maintain two sets of codes.

I tried layout my project directories as below:

--ProjectRoot <the root directory, all files placed in>
|--Common <place the common c# source files shared by both>
|--*.cs
|--ProjectForCE <place the *.csproj for WinCE>
|--Properties
|--CE.csproj
|--ProjectForPC <place the *.csproj for PC, Full .NET F>
|--Properties
|--PC.csproj

I tried to get the CE project and PC project to refer the c# files
reside in Common folder, but strange things occurred, the VS2005 copy
the whole Common folder into the project's own folder, doesn't refer to
the shared Common folder as i imagine.

The following layout also doesn't works:
--ProjectRoot <the root directory, all files placed in>
CE.csproj
PC.csproj
|--Common <place the common c# source files shared by both>
|--*.cs
|--ProjectForCE <place the *.csproj for WinCE>
|--Properties
|--ProjectForPC <place the *.csproj for PC, Full .NET F>
|--Properties
Properties will be created in ProjectRoot automatically when you open
the CE.csproj or PC.csproj, i cannot find way to moving Properties to
its own project dir.

So I think that maybe ms doesn't recommend this kind of directory
layout, but what is the legit?

Any other ideas?

Thanks,

ping235