I don't think its the FW410 because I have the same problem on my MacBook using the Built In Audio. This is what the Logic manual says about auto input monitoring on page 357:
"If Auto Input Monitoring is switched on, you will only hear the input signal during the
actual recording - before and afterwards, you will hear the previously recorded audio on
the track, while the sequencer is running. This helps you to judge punch in and punch
out points when punch recording. If Auto Input Monitoring is switched off, you will
always hear the input signal. Auto Input Monitoring, when switched on, also allows you
to hear the input source when Logic Pro is stopped, making it easy to set levels."
Lets say i have an audio recording on a track from bar 1 to bar 9 and i want to use Autopunch to record over bars 4 and 5. I turn on auto input monitoring, turn off software monitoring and press record. Instead of working as the manual says, i don't hear the input before, during or after the autopunch zone, although it is still recorded on these 2 bars. Before and after the autopunch zone i hear the previous recording but during the autopunch zone i hear nothing. If i turn auto input monitoring off i get the same result. It makes no difference having it turned on or off.
If i turn on software monitoring and i press record i hear the input signal before, during and after the autopunch zone whether auto input monitoring is turned on or off.
Maybe im not using it correctly, but it just doesn't seem to do anything.