Here is the way to zero out reset the 700P. You will even get a reformatting message. The only change to this is in step 6 you will get the access logo when you get that after a few seconds release the power button and then you get the push up or down to erase data. Push up and it will go to a reformatting screen. After it reformats it will go totally black and then reboot to the stylus screen.
I actually found this on the TreoCentral site here:

Palm's knowledge library lists an alternative way to "zero out" 700P devices that can be found at ID: 15574 in their support knowledge library

Factory Reset for Treo 700p smartphones

If you've set a password on your smartphone, any hard reset will automatically become a Factory Reset. With this method, you'll enter a password and then perform a hard reset.

1. On your smartphone, launch the Security application.
2. If the Password box says "Unassigned," tap the box and create a password for your smartphone.
3. Once the password has been set, disconnect your smartphone from the AC charger and take off the battery cover. Do not remove the battery yet.
4. Hold down Power/End .
5. While holding down Power/End , remove the battery. Then insert it again.
6. While still holding Power/End , the screen will show the Palm logo and a progress bar. Then the circular Palm Powered logo (orange) will appear. Release the power button when you see the Palm Powered logo (blue with silver).
7. A message will appear warning that you are about to erase all the data stored on your smartphone. Press UP.
8. If you performed this reset correctly, the screen will go blank after several minutes, and you will not be able to turn on your device. The charging LED will not light up. (any other activity - such as the Palm OS logo and then the Applications launcher appearing - means the reset was performed incorrectly; try again)
9. Your device will appear "dead." To wake up your smartphone, perform a soft reset.