I have a Partner Mail VS that loses memory of the date and time when the power is turned off. I have heard that there is a battery on the PMVS that can be replaced. Does anyone have any documentation on what type of battery it is and where it is located on the card? Or instructions on replacement? In the PMVS book it says to reprogram the time on the Partner and it will synch with the PMVS in a minute. That didn't work.