Australia Post Addon For Vendor's Contract Rates

Looking for an Add-On that will use a Vendor's own Australia Post contract rates via API and display the rates to the customer.

CS-Cart already has a native Australia Post API that will give live generic non-contract rates but it doesn't allow for the addition of your own contract rates which can be substantially cheaper than the generic non-contract rates.

Just about every Australian ecommerce business will have an account with Australia Post with their own negotiated contract rates. Everyone of my current vendors has an AP account and would dearly like to use it instead of setting up manual tables.

See here for AP developer information:

This add-on would probably do very well being listed for sale on the CS Marketplace as it would be very appealing to Australian users. This would also help to defray the cost so one user (such as myself) will not have to shoulder the full cost of development but could be sold at a far more reasonable and attractive price for all potential Australian users.