Just got my WM today, looks great. The only thing I can't figure out is if the valves are two way or not. Is there some way I can inflate it to my desired pressure, take the pump out, and then screw on the lid without any air loss? I may not be doing it right because so far that has been the only way I have been able to do it. Or are they just one way and do I therefore have to inflate, pull it out quick, and quickly try to screw it in? Any help would be appreciated.