Venting these items is really simple. The biggest thing to do is to run good lines to a spot above your typical water line. Recently a jeeper wrote about piping all his vents into the bottom of the rollbar, where it meets the floor. His thinking was the roll bar will most likely never get soaked and filled up. He thought it was an "out of the way" spot. He also planned on drilling some small 1/4 inch holes in the top of the roll bar to allow air to "flow". His idea was to connect his lines to a threaded fitting with a vacuum line hose end.
Others have bought special vents that you can find on the internet. They are a little more "hard core" than the OEM stuff and work well. The biggest thing is to use your head and make it work.