Address book Custom fields

Hello.

I am making a script to synchronize our intranet with address book via web services. I have some fields on our intranet that are not available in the address book. Is there a way to define custom fields on the address book via scripting?

Edit: I think I posted on the wrong section. I guess this is more Applescript OSX. Anyways any pointers will be appreciated.

Moving to OS X forum.

Thanks! I hope someone can help me with this. I have searched around with no clear pointers. I found this, though: http://developer.apple.com/documentation/AppleApplications/Reference/SyncServicesSchemaRef/Articles/Contacts.html#//apple_ref/doc/uid/TP40001541-209998

But nothing on how to get to these “custom fields” with applescript.