Hi,
as an addition to the prev. post I have tried to use AddInMon.exe from
Microeye (thanks guys).

But it seems I can not make it run as expected. When ActiveSync launches
Outlook, I can see in TaskManager that AddInMon is started shortly and
then it disappears from the running processes. It does not disconnect my
addin (I have MessageBox.Show in OnDisconnect method so I can see when
the addin is disconnected).

Does anyone has experience with AddInMon.exe and .Net addins? Any clues
what can be wrong?

This is what I have in Connect class (only relevant info about
AddInMon):

private bool IsAddInMonProcessStarted()
{
System.Diagnostics.Process[] processes =
    System.Diagnostics.Process.GetProcessesByName("addinmon");

return (processes.Length > 0);
}

[DllImport("kernel32.dll")]
private static extern long GetCurrentThreadId();

public void OnConnection(object application,
Extensibility.ext_ConnectMode connectMode,
object addInInst, ref System.Array custom)
{
if (((Outlook.Application)application).Explorers.Count <= 0)
{
    //No GUI. Start AddInMon.exe to listen.
    System.Diagnostics.Process currProcess =
        System.Diagnostics.Process.GetCurrentProcess();

    //use kernel32.dll, see below
    string threadId = GetCurrentThreadId().ToString();

    string addInID = ((Office.COMAddIn)addInInst).ProgId;

    if (!IsAddInMonProcessStarted())
        System.Diagnostics.Process.Start
(Globals.FileNamesAndPaths.AppPath + @"\addinmon.exe",
        addInID + " " + currProcess.Id.ToString() + " " +
threadId);

    return;
}
...other init code goes here ...
}

Cheers
Sunny