Normally these vans have to go on a diagnostic machine/scanner thats capable of reseting the service oil interval...you of course try this procedure below..however that doesnt work then you'll certainly need to find garage or a good mobile tech with the proper equipment to reset it for you..should on take less than 10minutes to do on machine..
Procedure to try - Oil service
1. Ignition OFF
2. Press and hold trip reset
3. Turn Ignition ON "do not start"
4. Display should count down from 10-0
5. Release trip when display count down reaches 0
6. Service indicator shows (=0)
7. Turn ignition off
8. failing above after several attempts? Diagnostic tool required to reset