SQL ODBC driver for NAV2015

I'm currently working on a ODBC driver connection for SQL to connect between NAV2015 and a 3rd party solution.
I created a new Data Source in the ODBC Data Source Administrator->System DSN->Add, and choose: SQL Server Native Client 11.0.
I tested the DataSource connection in Excel and it recognizes the NAV2015 database on the SQL server (SQL2012) but I can only do a read but not a write. The driver setup is defined as read/write.
Any ideas?