Complete CubeCart V5 Checkout by Amazon module then convert to CubeCart V4 and CubeCart V3 versions

This is a repost of a previous project which was not undertaken as we have decided to expand the project to not only include the completion of a couple of outstanding issues with the CubeCart V5 version but to also include the delivery of CubeCart V4 and potentially CubeCart V3 versions. CubeCart V5 version We have an almost complete and working "Checkout by Amazon" module for CubeCart V5 but there are a couple of issues that need fixing / completing. The module correctly allows customers to login via their Amazon account and choose a payment method to complete payment of the order (all of this functionality has been tested and confirmed as working by Amazon themselves) but there are some outstanding issues : 1) The "Checkout by Amazon" button needs to be placed on the cart page using the CubeCart built in hooks so that customers can login to their Amazon account at that point - see pages 4 and 5 of the attached document "Checkout by Amazon Integration for UK (Inline).pdf" and also sections of the other integration documents 2) Currently the payment process doesnt use the IOPN API to confirm when payment has been reserved on the customer's account - only at this point should the order should be changed from Pending to Processing and can therefore be shipped by the store owner. See page 23 (Handling Settlements) of the attached document "[login to view URL]" and also the attached document "[login to view URL]" 3) When the order is fulfilled or cancelled by the store owner, Amazon should be updated accordingly - again please see page 23 (Handling Settlements) of the attached document "[login to view URL]" and also the attached document "[login to view URL]" This should be implemented using the built in hooks within CubeCart V5 so that core code is not changed. A testing scenario document "[login to view URL]" has also been attached and the delivered solution should pass all of the included tests CubeCart V4 and V3 versions - Once the changes above are completed, we want it back ported so that it works as an "Alternate Checkout" module for CubeCart V4 and as a payment gateway for CubeCart V3 A full working dev CubeCart V5 store will be provided which includes the working version of the Amazon gateway as it currently has been developed. V4 and V3 dev stores will also be provided which can be used for development if you wish but final testing and sign off will need to be done in these environments. Full installation instructions for each version will also be required Amazon have recently released some small changes to their code for security purposes and these should be incorporated in all three version. Details can be found here : [login to view URL]