[3.5]User joined to domain but autodiscovery is not working due to missing cert?

[Torsten73]

I noticed in 2 installations a difference in certificates for autodiscovery.

My older [3.5] test setup has a cert autodiscovery. I startet it from beta stage.
My newest installation has many troubles with outlook 2010.
the setup guide like https://wiki.zentyal.org/wiki/En/3.2/OpenChange_%28Microsoft%28R%29_Exchange_native_replacement%29
is not working, because outlook will not configure himself like it should. The user is joined to domain. I needed to manually configure the exchange outlook profile. When i do this, outlook 2010 connects to exchange, but can´t download and sync anything (although i accept the warnings and the user sing´s in every outlook start). Testing autodiscovery from outlook fails.
I think this is the reason for a nonfunctional outlook.

Why is the cert missing?
how can i create it by myselve? like every other cert? Something i need to know?