>>
>>But now the challenge is to make that same dll work from VFP and I ran into the same problem - it doesn't find that .ini file. Since I can not test that DLL from VFP, I am not sure where to place that .ini file and how to name it. I sent this question to my colleague who developed that class.
>
>Sure you can (assuming you have the source to the .NET DLL). Open the .NET project up, select Debug, then Attach to process. Find the VFP instance and attach to it. Now you can set your breakpoints in the .NET code and they will be hit when your VFP code calls it.

There is another static class in this library

namespace Siriusware.Library
{
    static public class AppInfo
    {
        //static constructor.
        static AppInfo()
        {
            sModuleName = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name;
        }

I am trying this code

loAppInfo = loBridge.CreateInstance('Siriusware.Library.AppInfo')

but it just returns null. It has some static properties which I'd like to try to set, even though I'm not sure if calling the Cass class methods afterwards will use that AppInfo properties I set or it will use something different. My attempts to debug using the approach you suggested (e.g. click on Debug, attach to process (I select VFP9)) were unsuccessful - VS doesn't stop at the breakpoints I have in the code.