Planned Maintenance Work Orders w/o Settlement Rule

Hello Experts,

I have set up some maintenance plans which generate Notifications. Then the notifications are turned into Work Orders manually.

Now when we come to complete the work orders through transaction IW42 (Tech Completion) we are getting the error "Order cannot be completed; account assignment not maintained. - Message No. IW177

I have looked about this at it seems that the Work Orders do not have settlement rule assigned to them.

1 - How can i assign a settlement rule to teh order already created ??

2 - How can I make sure that the next Work Orders to be created will be automatically assigned the settlement rule ??

Thanks,

William