Sibilance with the VS series...what gives?

[Trippalot]

Hello. I am decently experienced in recording and recently I have been recording vocals with a AT4033. The tracks I've recorded so far are great except for one thing. I use a vocal processor on my VS880 to de-ess the input signal while recording to cut down on that not-so-good sounding hiss. The problem is, when I'm ready to do a final mix and I'm adding a touch of compression to the vocals, the hiss comes back. It's like, when I use the de-esser without the compressor, it works fine. Add the compression and the de-esser doesn't work. And I like the way the vocals sound; they are perfect except for the damned hiss on my "s's" and "t's." Any tips/suggestions? If I've left anything out, ask me and I'll tell you. Thanx.

Tripp