Thank you for the replies.

Now, I recompiled Python.Net with .Net 4.0 and get below working with
simple AAA.BBB.Adapter after reading

http://stackoverflow.com/questions/14520888/clr-addreferenceexample-file-unable-to-find-assembly?rq=1
http://stackoverflow.com/questions/13259617/python-for-net-unable-to-find-assembly-error?rq=1
http://sourceforge.net/p/pythonnet/bugs/17/
http://sourceforge.net/p/pythonnet/bugs/18/


Now I have below sample code(Adapter.proj has two c# files), and
experimented

Class1.cs
-----------
namespace AAA.BBB.CCC
{

public class Adapter
{
public string Function1()
{
return "AAA.BBB.CCC: Adapter Function1 Called";
}
public void Function2()
{
Console.WriteLine("AAA.BBB.CCC: Adapter Function2");
}
}

public class Network
{
public string Function1()
{
return "AAA.BBB.CCC: Network Function1 called";
}

public void Function2()
{
Console.WriteLine("AAA.BBB.CCC: Network Function2");
}
}
}

namespace AAA.BBB
{
public class Adapter
{
public string Function1()
{
return "AAA.BBB: Adapter Function1 Called";
}
public void Function2()
{
Console.WriteLine("AAA.BBB: Adapter Function2");
}
}

public class Network
{
public string Function1()
{
return "AAA.BBB: Network Function1 called";
}

public void Function2()
{
Console.WriteLine("AAA.BBB: Network Function2");
}
}

}

Class2.cs
-----------
namespace AAA.CCC
{
public class Adapter
{
public string Function1()
{
return "AAA.CCC: Adapter Function1 Called";
}
public void Function2()
{
Console.WriteLine("AAA.CCC: Adapter Function2");
}
}
}

Then, I got below. It seems working great.

C:\Automation\PythonNet>nPython.exe
Python 2.7.3 (default, Apr 10 2012, 23:31:26) [MSC v.1500 32 bit (Intel)]
on win32
Type "help", "copyright", "credits" or "license" for more information.
u'Adapter.dll'
<System.Reflection.RuntimeAssembly object at 0x052E5828>
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'Adapter' is not defined
u'AAA.BBB.CCC: Adapter Function1 Called'
AAA.BBB.CCC: Adapter Function2
u'AAA.BBB.CCC: Network Function1 called'
u'AAA.BBB.CCC: Adapter Function1 Called'
u'AAA.CCC: Adapter Function1 Called'
My questions are

1. I don't know how to specify different namespace of class when creating
an instance.
2. The class that I already have has similar above layout in a project.
Common project has many class files in it, and each class has different
name space and class name.
AddReference('Common') looks working and loaded, but can't import.
<System.Reflection.RuntimeAssembly object at 0x052E73C8>
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named Network
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named Network.Common
Difference is that Common project has [Serializable] and enabled "Make
assembly COM-Visible"

[Serializable]
[Description("SimpleDictionary")]
public class SimpleDictionary : ISimpleDictionary
{
...
}

Any thoughts?
Wonder if there is a way to list available class after AddReference().

Thanks,
Spark.