If subparagraphs (a) 1, 2, or 3 of SP A70 is met, Engine using flammable liquid can be transported as Not Restricted. If the engine is driven by flammable gas or fuel cell, thence you need to meet all of the subparagraphs (b) 1, 2, 3, and 4 of SP A70. In the lower portion of SP A70, there is a reference to the shipper requiring prior arrangement with the operator refers to when there are multiple engines to ship on a pallet or ULD. If there is only one engine, this provision does not apply. I assume that the base of this ULD is not airworthy and not compatible with the aircraft restraining system.
Therefore, this ULD must be mounted on an airworthy airline owned pallet which is compatible with the aircraft restraining system. As long as that shipper owned ULD satisfies the provisions of PI 956, it can be used as outer packaging. The transportation charge will be levied on the gross weight of the ULD.