I'm installing bm3.7 on a nw6 server. Service packs applied : bm37sp +

Everytime I'm accessing a https page, I receive a http500 internal
error page (not from Bordermgr and with different browser versions)
The setup is as follows:

Bordermgr is proxy server for all clients.
Bordermgr connects to a trendmicro viruswall server as cache hierarchy

client. The viruswall has access to the internet.
Between bordermgr & the viruswall is a Checkpoint NG_AI firewall.

When bordermgr is not a cache client from the viruswall and goiing
to the internet, I don't have these problems. Everything works fine.
If I point my browsers proxyserver directly to the viruswall (withoutbordermgr) I also don't have these http 500 error messages for https
So both producs separately don't give any problem.

When I receive this error message it's instantly. So I don't think
it's a
time-out or something. (fw rules checked --> no drops)

Anyone a clue?