Named Semaphore shared between windows application and service

Hi all,

I'm trying to use a named semaphore in order to trigger a windows service action by an external application.

My windows service code look like this:

        private void Run()
        {
            try
            {
                bool created;
                namedSemaphore = new Semaphore(0, 1, Settings.Default.MutexName, out created);
                if (!created)
                    throw new ApplicationException(string.Format("Named semaphore {0} was already created by another process", Settings.Default.MutexName));
            }
            catch (Exception ex)
            {
                svc.WriteLogEntry(string.Format("Failed creating named semaphore. \r\nException was: \r\n{0}",
                    ex), EventLogEntryType.Error);
            }

            try
            {
                while (true)
                {
                    namedSemaphore.WaitOne();
                    PerformAction();
                }
            }
            catch (ThreadAbortException)
            {
                Thread.ResetAbort();
                workerThread = null;
            }
            catch (Exception ex)
            {
                svc.LogException(ex);
            }
            finally
            {
                namedSemaphore.Close();
                namedSemaphore = null;
            }
        }

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The code triggering the action in the windows service looks like this (resides in an external application):

        private void RunTrigger(object arg)
        {
            Semaphore namedSemaphore = null;
            try
            {
                namedSemaphore = new Semaphore(0, 1, "Action");
                namedSemaphore.Release(1);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
            finally
            {
                if (namedSemaphore != null)
                    namedSemaphore.Close();
            }
        }

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My problem is:
When running the service code as a console application everything works.
But when the code runs as a windows service, execution remains blocked in the WaitOne code, and it doesn't respond to the semaphore's trigger from the 2nd application.

Any help would be greatly appreciated.
Thanks.