Mandatory Person Responsible Field In Maint Order

Hi,

I wanna do mandatory the person responsible field in maintenance order.Is there any standard configuration to do mandatory this field only in Maintenance order.I dont wanna do in notification.I searched but I m unable to do this.

I have another option that is screen variant for IW31 It is working.But I want to know more about it.

Thanks

Regards

Gaurav Solanki