I have seen the info on creating custom templates and can handle that bit (I think!) I know that creating customised vhosts templates is more complicated so (at least to begin with) will just work with the default vhost. I get a bit lost with Apache directives and would be grateful for any help you can give on that part of the problem. default-virtalhost.inc has RewriteRule and zzz_SOGo.con has RequestHeader set. I did see this post:
which seems to be fairly close to what I am looking for but is a bit old. I thought that the actual redirect took place in 30SOGo part of default-virtualhost.inc. Nevertheless, I will give it a go and report back.
Thanks for your support and the great product that NethServer is!