Dear Friend,
Now there is no separate procedure for Nepal and the general export procedure to be followed. Pl. refer the relevant Notification issued under Rule 18 band 19 of CER,2002. IN case if you want to pay the Duty, and if my rememberence goes correct, the amount of rebate to be given to his majesty of Nepal. Suggest you to pl. go through the Notifications and CBE & C Manual.
Further, regarding delivery, you may have to have the terms in the PO and once the buyer is taking goods at your Delhi office, by attaching the transportation for his known transporter the responsibility of delivery/handing over at the specified land customs station obviously lies on the customer and not you. It is better that you have to take acknowledgement for receipt of consignment from the customer at Delhi office which will relieve you from the obligation of delivering the goods at land customs station.
Regards
Suryanaarayana