It required several hours to determine why my sites were not compressing but here is what you MUST add to the bottom of the httpd.conf (apache congifuration file in cwp)
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4.[0678] no-gzip
BrowserMatch bMSIEs7 !no-gzip !gzip-only-text/html
BrowserMatch bOpera !no-gzip
Header append Vary User-Agent
DeflateCompressionLevel 9