Hi Yvan,
Yes now you have got it.
Unfortunately we are not allowed to change any business logic ( stored procedures and others )
Yes, another method as you have suggested is to use "dbcc set_identity_burn_max" as an additional step when standby is made active. This will help to sync the next IDs for the related tables.
But actually they are reluctant to accept this method.
Thanks & Regards,
Shiva