Garmin Foot Pod Waterproofness

Was considering getting a Garmin GPS watch, maybe the 305 since its only about £100now, or maybe the new 110 which is not much more. I do however already have a forerunner 50 with a HRM and footpod, which to be honest would probably do most of what I need already (ie distance, pace, HRM) but without the geeky option of plotting my runs on a map afterwards. I've tried to avoid using the footpod off road since I'm convinced it will die the first time my foot is submerged in water and/or mud. The foot pod I have is not the most recent model, but the one before that (not as small, but it still clips on).

Anyone done any field testing to reassure me?? Or alternatively has anyone who uses one tried to make it more watertight (with tape or some sort of sealant)?