[squid-users] Content-encoding header lost when getting a "304 Not Modified" reply

Hi

I'm having problems with a SAP Netweaver portal. For 99% of the users it works fine, but for a few users it's just the top information of the page that loads.
Some of these users are having Squid proxies, but different versions..
The problem seems to be related to some proxies not sending HTTP 1.1 requests.
I've looked at the headers and noticed that some .js are referred to at least two times.
The first reply correctly states that the content is compressed, but the second reply tells the client to use the locally cached copy, and does not give the "content-encoding: gzip". This causes Internet Explorer to try to use the compressed locally stored file, but not uncompressing it.
Has anyone had this problem before?

What's the solution? Not using compression at all?
Sadly i don't have the possibility to check the exact replies from the server.. Guess that would tell me who's really the bad guy here :)

Thanks
Johan Sarnstrom
WM-data Infra Solutions AB

First request:
GET http://xxxx/irj/portalapps/com.sap.portal.pagebuilder/scripts/pagesupport.js HTTP/1.0
Accept: */*
Referer: http://xxxx/irj/portal
Accept-Language: es-gt
UA-CPU: x86
Pragma: no-cache
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322)
Host: xxxx
Proxy-Connection: Keep-Alive

First reply:
HTTP/1.0 200 OK
Content-Length: 6579
Expires: Mon, 17 Dec 2007 14:44:01 GMT
Date: Mon, 10 Dec 2007 14:44:01 GMT
Content-Type: application/x-javascript
Server: SAP J2EE Engine/6.40
Last-Modified: Tue, 19 Dec 2006 16:08:04 GMT
Cache-Control: max-age=604800
Content-Encoding: gzip
X-Cache: MISS from proxy
Via: 1.0 proxy:3128 (squid)
Proxy-Connection: keep-alive

Second request:
GET http://xxxx/com.sap.portal.pagebuilder/scripts/pagesupport.js HTTP/1.0
Accept: */*
Referer: http://xxx/irj/servlet/prt/portal/prtroot/pcd!3aportal_content!2fcom.tetrapak.ebusiness!2fframeworkpage!2febusiness_desktop!2fframeworkPages!2fcom.sap.portal.frameworkpage!2fcom.sap.portal.innerpage
Accept-Language: es-gt
UA-CPU: x86
Proxy-Connection: Keep-Alive
If-Modified-Since: Tue, 19 Dec 2006 16:08:04 GMT; length=6579
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322)
Host: ebussapm.tetrapak.com
Pragma: no-cache

Second reply:
HTTP/1.0 304 Not Modified
Expires: Mon, 17 Dec 2007 14:33:05 GMT
Date: Mon, 10 Dec 2007 14:33:05 GMT
Server: SAP J2EE Engine/6.40
Cache-Control: max-age=604800
X-Cache: MISS from proxy
Via: 1.0 proxy:3128 (squid)
Proxy-Connection: keep-alive
Received on Tue Dec 11 2007 - 03:23:25 MST