GW, its parts (GMS; WebMail) and the base-OS

Hi,

when choosing NCP-Cluster (OES) as GW base I get an perfect PIM-System!
High available and comfortable for users and admins.

But:
If I deceide to use GMS (GroupWise Mobility Service) then I have to buy
an SLES12 because the use of OES2108 as base for GMS18 is not supported?!

Whats about GW-WebMail? Same issue?
What will happen when GWAVA products comes in? (Newly descripted as
Enterprise ....) Ubuntu-VA ... indeed?

SLES is really fine. But it is (now) an other company. And SLES needs
more then the servers they needs an additional SMT bacause SMT supports
NCC OR SCC.

Is there anything of document I can clarify this? Or who is the mananger
I can ask this behavior?

Bernd