PHP Integration with Peachtree

I have a potential client that needs an e-commerce site designed and they want their online inventory synced, in real time, with their peachtree software. So far, the best solution I’ve found is that they could export their inventory via peachtree in an excel file and upload it to the website to update the inventory, but this is not good enough. It really needs to be “real-time.”

I can give more details, but first… have any of you developers had experience with something like this? …with peachtree or quickbooks… anything?