Predefined service contract

Gurus,

Can we create any predefined rate contract. My client have yearly based rate contract with vendor. In this rate contract they have segricated the amount for each activity. for example - change of motor -100 rs, change of pump 200.

Whenever the service contractor done the job they have raises the bill for the activity.

Through external services can we map this process?

Activity wise i need to assign in service specification page (order screen) . Is it possible to capture the cost from contract activity wise?

for example if assigned the line item 010 work as "change the motor" it should be directly added to contractor account after accpetance of service entry.

kindly suggect me how i can capture this activities.

Thanks and regards

G.Sathish