This generally is the kind of work we get paid for and where the end result becomes property of our employer or client so I doubt whether you'll get it for free here.
Besides that the required segregation of duties fully depends on the acknowledged risks which in turn depend on the way your HR system will be used. I think you should talk to your functional consultants to determine which functionality will be implemented and talk to internal auditors about the risks they want to be dealt with.
A purely technical approach will most probabely fail.
Do feel free to come back to us with technical issues.
Jurjen
