[TYPO3-english] Connection problem - pagetree not rendered - https - load balancing

[Roberto Demontis]

Hi,

i have a problem accessing the backend page from any browser, using https and in a load balancing scenario. The page tree doesn't appear for any item of the left menu web modules. 
Our web farm consists of two windows web servers with wamp and a load balancer where is installed the digital certificate for https communication with clients. But all the traffic between Web servers and load balancer goes via http. 
Monitoring traffic from the browser by fiddler and Firebug (.net tab) we can observe the absence of any Ext.direct request and, after a few seconds, it appears a message connection problem. According to fiddler monitoring it happens simoultaneously the following https get:  
"typo3/ajax.php?ajaxID=BackendLogin%3A%3AisTimedOut&_dc=1452853020857&skipSessionUpdate=1".

If we access the web site in http all works fine. Any ideas about a possible solution?

Thanks a lot.