In Preferences -> General -> Mime Viewers (or the most bottom item in General menu, can't remember how it's in English, might be External Viewrs) you'll find the definitions for different filetypes. Search for zip and make similar entry for lzx, type:application/lzx, extension: lzx , action: Save to disk
Note that some servers send false header information (or none) which makes some browsers handle the files incorrectly.
- Sami