Bang Guy's recommendations are right on, and are the best solution. However, you can try using a drinking straw, or piece of airline to vent the standpipe as well. I've done this in a pinch and it does work, but takes a bit of futzing.
What you do is take whatever tube you use and slide it into the standpipe (don't let go!). Now, SLOWLY begin to draw the tube out of the standpipe until you find the "sweet spot" where the noise stops. Then secure the tube in that spot and voila. Like I said, sometimes you nail it right off the bat, and sometimes you really have to mess with it. Try different sides of the standpipe as well if you have trouble.