Thanks for replying @Jakev
As you said "Get the roles and responsibilities roughed out, and get it signed by a senior"..
This means it will be a certificate detailing roles and responsibilities and designation only and no other detail like date of joining, salary etc. and signed by senior and supported by all other docs..
Also can it mention that this person is carryimg out duties as per deptt.'s published manual (relevant pages attached alongwith..)
Yes- your understanding is correct.