problem triggering session using addTriggerConnection

Hi,

I am trying to trigger analog input recording using addTriggerConnection.

startForeground(s)
s = daq.createSession('ni')
addAnalogInputChannel(s,'Dev1','ai0','Voltage');
addTriggerConnection(s,'external','Dev1/PFI1','StartTrigger')
startForeground(s)

a momentary button is connected to PFI1 and transmit a 5V signal but nothing happens when I press it.

The property s.IsWaitingForExternalTrigger remains false too. What am i doing wrong? I am using a NI 6036e.

Cheers,

Roberto