Ok, by trial and error I think that I now understand a bit of it.
took a certificate from out webserver, uploaded it to the certificate store, and iPhones are now getting this certificate displayed on connect. iPhones are asked to approve the certificate. Android just connects without any promts.
Some windows clients connects without problems - others will fail unless you manually create the wifi network, edit it and deselect the "validate server certificate" option.
The certificate is valid. It has been issued by a trusted authority.. Then name of the certificate belongs to a server with another IP address though..
How can I let every connecting client act like an android: just connecting without certificate approvement or manual wifi creation?
Regards, Lars.