Exporting from one gateway and importing to another will not work. This is due to the nature of tokenization itself, which makes such an option impossible.
When you add a credit card to a gateway, they gateway takes the unmasked credit card information and stores them in their PCI compliant system, which is highly secure and tightly regulated. In order for applicatons such as iPayment to utilize the credit cards in a secure way, a 'token' is created.
This tokenized representation of the credit card is unique for the gateway, since it was generated by them and linked to the corresponding credit card information.
This means that moving a token from one gateway to another would result in an error due to the new gateway not having a linked record for the old token in their system - most gateways have different formats for the tokens as well as validation that the tokens we pass to them adhere to their specific format.
In the end we'd likely be left with a 'token not found' or 'incorrect format' error of some sort, so this is not possible.