Hi there,
I just got my WP-V1. With the housing, an additional sheet is enclosed to activate the Underwater mode. Here are the instructions (camcorder must be powered on during the full procedure):
1. Remove SD Card from the camcorder
2. On the lcd panel, press the camera<>play button (the one on the right to the playlist button). If the single photo screen appears, move the zoom lever toward W.
3. At that point you are in the review pictures/shots mode. Go to the photo tab and select the SD tab (if you have one , not on my HF200) using the navigation arrows
3. Press start/stop (back of the camcorder), photo (top of the camcorder) and video snap (same side than the panel of the camcorder) for at least two seconds.
4. You get a message asking you if you want to activate underwater mode. Use the navigation arrows to say yes and press SET. Otherwise, selecting No will cancel the operation.
5. The camcorder will reset and automatically turn off. When it turns on , set date/time .
After that, the underwater mode can be selected in menu => exposure program => far right (portrait or something else) => press set to access other program . The underwater mode icon is a bubbling fish.
Have fun