How to Add rel=author to vBulletin 4.2 ???

[PingCity]

This question is asked by so many others so far but nobody has received any answer. I am sure it is "not" impossible to add rel=author to vBulletin 4.2 because we already have a thread about ding it for vB 3.x here:
https://vborg.vbsupport.ru/showthread.php?t=266259

Is there anybody who can help us about adding rel=author to VB4.2 ?

Thank you in advance.