Hi Mohan,
As a consultant, you should question the business purpose of the non-numeric character in the personnel number, rather than building something cumbersome to emulate it.
Since the 1980s there isn't really a good reason for this practise sny more (back then it was used to code further info into the personnel number to save a few bytes of storage space).
I am confident: if you discuss why this is supposed to be required, you'll find a better way to deal with that requirement than bending the system and creating a cumbersome process. I've seen close to 50 implementations and almost half of them talked about coding sth into pernr at the start (particularly in the 90s), but eventually none of them needed it.
Good luck
Sven