I have get the solution for this issue. please check my code that added into FedexComputationMethod.cs file that exist into Fedex Plugin. Insert this code after 110 line no of this plugin file. also check my image that added that much easier for you.
#region Customization to make this plugin for india
if (getShippingOptionRequest.CountryFrom.TwoLetterIsoCode == getShippingOptionRequest.ShippingAddress.Country.TwoLetterIsoCode)
{
request.RequestedShipment.CustomsClearanceDetail = new CustomsClearanceDetail();
request.RequestedShipment.CustomsClearanceDetail.CommercialInvoice = new CommercialInvoice();
request.RequestedShipment.CustomsClearanceDetail.CommercialInvoice.Purpose = PurposeOfShipmentType.SOLD;
request.RequestedShipment.CustomsClearanceDetail.CommercialInvoice.PurposeSpecified = true;
request.RequestedShipment.CustomsClearanceDetail.CustomsValue = new Money();
request.RequestedShipment.CustomsClearanceDetail.CustomsValue.Currency = "INR";
request.RequestedShipment.CustomsClearanceDetail.CustomsValue.AmountSpecified = true;
request.RequestedShipment.CustomsClearanceDetail.CustomsValue.Amount = 100;
request.CarrierCodes = new RateServiceWebReference.CarrierCodeType[1];
request.CarrierCodes[0] = RateServiceWebReference.CarrierCodeType.FDXE;
}
#endregion Customization to make this plugin for india