interface for Lexware faktura + auftrag plus

Hello, We need a connection between the useraccounts of our Website (working with “Auction Factory” for Joomla) and the Program “Lexware faktura + auftrag plus”. So, all Account details, like balance, bills etc. should be managed with “Lexware faktura + auftrag plus” and of course, automatically adjusted in the component. Please someone who has experience with Lexware and who know which functions it has. It would be an advantage if you can speak german. THX!