Since those links are now broken, here is the relevant text:
To use Windows Authentication, where the connection is authenticated using the identity of the user running the Ignition gateway, you must first install the Microsoft JDBC driver package. The driver package can be found at: msdn.microsoft.com/en-us/sqlserver/aa937724.aspx
Burried in that package, you will find a sqljdbc_auth.dll file. Copy the correct file for your architecture (64 vs 32 bit) into the following two directories:
\Ignition\tomcat\webapps\main\WEB-INF\lib
and
\Java<jre folder>\bin
(ie: C:\Program Files\Java\jre6\bin, and make sure you use the folder for the right architecture)
Then restart the Ignition service.
Here is the full Knowledge Base Article: Microsoft SQL Server Connection Guide for Ignition