ExecuteComplete ADODB Connection event not fired with adAsyncExecute parameter - events

Question

I have a problem trying to catch the completion of a stored proc execute asynchronously.
Below my code VBA (in a class module named clsAsync):
Option Explicit
Private WithEvents cnn As ADODB.Connection
Private Sub cnn_ExecuteComplete(ByVal RecordsAffected As Long, ByVal pError As ADODB.Error, adStatus As ADODB.EventStatusEnum, ByVal pCommand As ADODB.Command, ByVal pRecordset As ADODB.Recordset, ByVal pConnection As ADODB.Connection)
MsgBox "Execution completed"
End Sub
Sub execSPAsync()
Set cnn = New ADODB.Connection
Set rst = New ADODB.Recordset
cnn.ConnectionString = "connection to my database SQLSEREVER"
cnn.Open
cnn.Execute "kp.sp_WaitFor", adExecuteNoRecords, adAsyncExecute
End Sub
This class is PublicNotCreatable.
To call the sub execSPAsync from a module I use the following code:
Sub testASYNC()
Dim a As New clsAsync
Call a.execSPAsync
End Sub
The stored procedure is very simple:
alter PROC kp.sp_WaitFor
AS
WAITFOR DELAY '00:00:05'
My problem is that the event ExecuteComplete is not fired at all, while if I comment the adAsynExecute parameter all is working fine.
Any idea on how to solve my question?

Answer 1

I solved my problem replacing the calling code:
Sub testASYNC()
Dim a As New clsAsync
Call a.execSPAsync
End Sub
with this new code:
Private a As clsAsync
Sub testASYNC()
Set a = New clsAsync
Call a.execSPAsync
End Sub
In the async mode, the object "a" is no longer available at the end of the procedure (scope visibility issue).