on HP-UX (by default anyway), you can change ownership of a file as a normal, non-root user. This means you can do a cp -p to copy files retaining permissions and ownership on HP-UX file systems. However, if using NFS, be aware that the underlying NFS server's operating system controls privileges to file ownership. Therefore most Linux/Solaris/NAS boxes that are NFS servers and mounted on HP-UX, will not allow a successful cp -p for retaining ownership (or chown by a normal non-root user).
Specifically it can be an issue on EMC Celerra NAS servers, but there's a way to change it:
To change this behavior you can change the Celerra server parameter, rstchown to 0, the default is 1.
Here's a copy someone posted: http://www.scribd.com/doc/6116381/Celerra-Network-Server-Parameters-Guide-5639-A03
Sets restricted file ownership.0 = Allow the owner of a file to change the file ownership or group ID to any other owner or group because chown and chgrp follow the less restrictive POSIX semantics.1 = Allow only the superuser to change the owner of a file. The current owner can change the group ID only to a group to which the owner belongs.This parameter applies to NFS, but not to CIFS.