Helper applications: how to set?

[David-Artur Daix]

I'm having some trouble making OmniWeb pass downloaded files to the proper
helper application for post-processing, and I can't find anyway to access
those settings either in the Internet preferences pane or in OmniWeb's
preferences. Namely, .hqx files are never handed to Expander, nor .gz file,
while .sit.hqx files are often sent to Word. The Inspector window is no
help, since all those files sport a ???? Type, for which, naturally, no
default application can be assigned. And I can't find a way to get at the
MIME and/or file extension settings. Internet Explorer, on the other hand,
offers, among its preferences, a file helpers section similar to that found
in the Internet control panel's Advanced Tab under Mac OS 9 and reproduced
in the Internet Explorer 5 (Classic) preferences. And it does call upon
Expander to decode .hqx and .gz files. I'm sure I'm missing something
obvious: can someone help me sort through this? Thanks.

D.