Hi vmxa,
AoI uses the reverse capture the flag option to simulate trading traffic from the colonies back to the VPs that are mostly near or on the tile of capitals. The decisive is the additional cash that comes from such a rawmaterial unit when escorted by a normal unit on a VP location. The addition of victorypoints is only secondary as there must be vps for that action, otherwise the reverse capture the flag option wouldn´t work.
To get the cash (and the VP so I never watched that addition as it is not so important), the following must be done:
1. The rawmaterial unit must be captured by one of your normal landunits. For doing this action a special button appears on the screen. This landunit now carries the rawmaterial unit and is marked with 3 !!! behind the unit name.
2. The rawmaterial unit must be brought on the tile where the victory point is located.
It can be brought to any VP. It must be brought "captured" by another of your landunits. If the rawmaterial unit moves itself on the the tile with the location of the VP, nothing will happen. If you move it to the capital and on the tile of the capital there is no location of a VP, also nothing will happen.
AoI is the Civ 3 scenario with the best integration of naval actions and sea trade, that I know. A new version (AoI v4) will come soon.