Import Data in WHMCS

Hi,

We are using a custom made software for managing our Domains and Web Hosting business. We would like migrate the same including the historical invoicing data of 7-8 years to WHMCS. We have been trying to import the data in to WHMCS , however we are facing the following issues.

1) When we try to re-create a backdated invoice in WHMCS using API, the invoice date is set to the current date. Even if we update the invoice date to an earlier date manually by updating the invoice date in database, WHMCS adds invoice line items with the current date as the registration date and an expiry say for 1 year from the current date. Hence the registration and expiry dates displayed are incorrect. What is the right way of doing this? how can we avoid editing the database directly?

2) When we are importing data we would like to maintain all invoices for a customer including expired services. How do we achieve this given the above limitations.

Please help, we shall be grateful for any pointers in solving this.

Many Thanks

Sinchan Rane