How do I run portage as portage in cygwin?

[qrwe]

Hi,

My question may come with a little n00b flavour..
I've read the step-by-step guide for installing portage on cygwin in the Gentoo-wiki. Great manual, but when it comes to creating users and groups, I lacked in my cygwin knowledge: http://gentoo-wiki.com/HOWTO_Gentoo_on_Cygwin#User_accounts_and_groups .
First of all, 'useradd' or 'groupadd' is not implemented in cygwin, so I guessed I had to do it manually. However, it doesn't matter if I create a portage group by 'vi /etc/groups' or do it the Windows-way - creating portage in "Computer Management" and then run 'mkgroup -lu > /etc/groups' in cygwin. Portage doesn't let me run 'emerge' in either way (except 'emerge --sync').
Secondly: What is "fake a user/group" supposed to mean?
Thanks for any help!