specify native library in java command line

My application is :
1. packed into 1 jar file
2. use sqljdbc4.jar
2. use a native library: "Microsoft SQL Server JDBC Driver 3.0".(use it in Ecplise and it works fine)
3. run by this command: "java -jar myapp.jar".

java version is jdk1.6.0_23

btw: I config all the class paths in the manifest.mf file

My application is failed to run, since it cannot find the native library. How/where to specify the native library location?