[amsat-bb] duplexer used as a filter

I'm trying to setup a remote sat station and need help with a desence filter. I was using a Diamond MX72-n and was experiencing water intrusion. I then checked the archives and consulted the group and went to the recommended Comet CF-416. Guess what, I'm still getting water into the duplexer. I thought that it was more suited to outdoor service on the recommendation of the group. So, before I take apart one of the duplexers to attempt to waterproof, does anyone know of a duplexer that is designed for outdoor use on the tower? I really don't have the room for a 12 foot + crossboom, so I need to resolve the desence with the duplexer. Any suggestions from someone who has solved this?

73 Jeff kb2m