We run SAP ECC 6.0 basis version 702, and are integrating with Magento for order management. I know that SBOeConnect :eCommerce Integrated with SAP Business One ERP extension exists, but I do not know if this works with our SAP installation.
(SAP ECC 6 and Business One are two very different beasts.)
Has anyone experience with integration the two systems?
Does the extention support SAP ECC 6?
As far as I know that is the only extension. I would recommend contacting them to ask if it supports your version of SAP.
The other option would be to build a custom module. Using the APIs and a cron job you can setup automatic push/pull events to sync data or tie it to an event observer for an action like a new transaction. There are obviously a lot of variables depending on what you specifically want to do.