Great…using the IPfire for years…why should I read the f…ine docs again? 
Thanks, this will be the solution and I will test this evening…
Maybe a further question now appears: when switching from topology “net30” to “subnet”, it is necessary to change the (automatic generated before) content of CCD-Files for clients in static subnets (other than those in the dynamic adress pool).
Otherwise the client cannot connect with this message:
“ERROR: --ip-win32 dynamic [offset] : offset is outside of --ifconfig subnet”
(reason: interpretion change from local/remote to adress/submask by ifconfig)
So I´m now thinking about the default behavior of IPFire when “topology subnet” is set: will the automatic generated CCD-files for Clients in static subnets be generated correctly or do I have generally to adapt them? Maybe this depends on the topology-State before creating the first static adress pool?
(first thought, that would be the reason, why my server.conf always will be resetted when I changed anything to Road Warriors in exiting setup - quasi protective function, cause existing CCD-config won´t run any more with subnet topology?)