Web ERP intergration expert required

Are you an EXPERT in Web ERP? We urgently need someone to connect via PHP (and XML?) to an existing WebERP installation and send custom invoices, inventory, warehouse data, sales receipts among other data. The interfacing should also allow WebERP to in-turn update our existing system. e.g If an invoice is paid for in WebERP, we should subsequently get a response to our existing MySQL system. Please note that this job is for persons who have previous experience in WebERP. We have tried many people who have promised but it turns out they don't know how to interface with it. Please, only bid if you can work on it.