[CentOS] Change password and add user on RO filesystem

Hi everyone

I'm trying to create system with RO root filesystem, so i'm using /etc/sysconfig/readonly-root along wih /etc/rwtab and /etc/statetab.

Apart of numerous problems with services running on RO filesystem (which i'm constantly resolving adding entries to /etc/statetab) one thing popped up. I'm unable to add user or change his password. Error is 'cannot lock /etc/passwd; try again later.'.

After research it turns up (at least on Fedora, but i assume same on CentOS) some files being created in /etc. For example /etc/shadow.<pid>, and some others with PID in name. Obviously it's impossible on RO filesystem...

Is there any workaround (apart of remounting whole filesystem RW)?