activ sync/OWA/outlook anywhere : webserver application firewall

hi,

we try to configure it.

OWA is OK

activ sync is NOT OK

outlook anywhere is NOT OK

we have look this kb but it do not help us because do not explain exactly how to configure :

http://www.sophos.com/fr-fr/support/knowledgebase/115971.aspx

can you help us ?

here an exemple of log we have :

2013:05:02-16:01:17 fw reverseproxy: [Thu May 02 16:01:17.967301 2013] [proxy_http:error] [pid 11380:tid 4045990768] (70007)The timeout specified has expired: [client 37.161.231.24:50047] AH01102: error reading status line from remote server 172.16.31.12:443

2013:05:02-16:01:17 fw reverseproxy: [Thu May 02 16:01:17.967419 2013] [proxy:error] [pid 11380:tid 4045990768] [client 37.161.231.24:50047] AH00898: Error reading from remote server returned by /Microsoft-Server-ActiveSync

2013:05:02-16:01:17 fw reverseproxy: srcip="37.161.231.24" localip="78.224.128.139" size="434" user="-" host="37.161.231.24" method="POST" statuscode="502" reason="-" extra="-" time="310187258" url="/Microsoft-Server-ActiveSync" server="mail.avtis.fr" referer="-" cookie="-" set-cookie="-"

thanks