External timer in order to shutdown

Hi there all,
i just want to ask you a little question.

I'm a newbe and i finish to read some articles on gammon
about power saving of arduino.

I have a pulse counter tha i want to make it to save more power possible.
The problem is that i need a timer in order to know
the time between the last 2 pulses every about 5 minutes.

If i understant, if i power down the arduino, i lost the mills().
But if i use an external timer2 using a 32 KHz crystal
i can wakeup and have also the time.

First of all ... is this correct that i understand please ?
Thanks a lot
Denis

Can you please post Arduino questions to their forum?

http://arduino.cc/forum/

You can send me a PM (on the Arduino forum) giving me a link to that thread if you like.

Ok ... thanks in advance
Here is the post please
http://arduino.cc/forum/index.php/topic,132545.new.html#new

Thanks again
Denis