Noting that this is a sea crossing, most customs formalities are usually completed by the shipping agent.
In Dili, the customs did not even bother looking at my vehicle - the carnet was taken by the agent (SDV), and processed fully without either myself or the truck being present.
If your vehicle is not cleaned on the port itself, you will have to take it to the port on a low-loader or other transporter. Arrange the timing with the agent. (See the East Timor Country Info section for advice on vehicle cleaning.)
Once in the port, play it by ear. It is a very small port. I drove the truck onto the ship myself, after chatting with the Australian stevedore for Perkins.
Wharfage and Customs costs totalled US$130.
As for immigration, Dili's airport is a standard airport. Only on a matchbox scale.
Assuming you arrive before your vehicle, call into Perkins and introduce yourself. Determine the ETA of the vehicle.
Then go to the Customs Office (Perkins will give you a map showing the location). These guys are practical, helpful and down to earth. For me, they liaised with AQIS (the quarantine authorities), confirming their availability for the ETA of the vehicle.
You pay for the AQIS inspection in advance. For me, it was just under A$100.
Ask for the Unaccompanied Baggage form, and complete it prior to the inspection.
When the vehicle is available for inspection, advise the Customs lads, and arrange a time for the joint inspection with them and AQIS. If all is ok, after the inspections, the carnet will be signed, you settle wharfage and shipping charges with Perkins, and then start to play the game of Australian-rules driving.
The Customs Office will have given you a form regarding having your vehicle mechanically inspected by the Motor Vehicle Registrar (MVR), and the payment for the Personnel Third Party Insurance. The form advises that, upon Customs/AQIS release, you must go immediately to the MVR offices for the inspection/insurance registration.
So, go to the MVR office. The vehicle inspection does not have to be pre-booked: just turn up. There is a charge for the inspection.