Charles,
are you trying to add new customer records or edit exisitng ? There are several tables involved. Let me know what you want to accomplish and I can provide the info.

We have an integration to GP from our VFP app, when we started I recall we downlaoding a developer document from great plains site with data tables info. I wil try and locate, also we have an on staff GP person if you need more info.

Let me know,
Clark