Purchase Order Controlled by Release Budget Amount.

Dear Friend's

I have created project upto level 2 wbs element.with ext services.

In Budgeting,

In CJ30 Tcode i have allocated budget Rs.100000/-

In CJ32 Tcode i have released above mentioned same amount for WBS 1.

In Purchase Ordering,

While creating PO In ME21N Tcode i have taken services for WBS 1 for which PO net amount is more than Rs.100000/-

When i go for saving of PO.The system must show Error "PO Amount is more than Released Budget.

Pls tell me the customizing setting for above mentioned scenario.By doing this setting system must show error while saving PO.

Pls help me urgently.

Thanks & Regards,

Sandeep N.Theurkar