How to enable Budgetary control for secondary ledger ?

For my client, We have Primary and Secondary Ledgers and Accrual with Encumbrance Accounting is followed.

For the Primary Ledger, budgetary control and encumbrance accounting is enabled and is working fine but for secondary ledger, budgetary control is not getting enabled.

Also there are 5 Business Units linked to my Primary ledger, and so reserve for encumbrance account will be different for different Business Units based on the location (Segment 2 of the Chart of Accounts), but the current behaviour of the system is that it is allowing me to put only one account code combinations for reserve for encumbrance account.

Please look into the matter and provide the solution at the earliest.