installanywhere launched from ProcessBuilder is not able to take log4.configuration system property

I am experiencing a strange behaviour. I am launching an installanywhere exe from my java class using ProcessBuilder. I am passing some args for the jvm like -DSystemRoot="C:\Windows" -Dlog4j.configuration=file:"<path to log4.xml>" -DLOG4J_CONFIG_FILE=file:"<path to log4.xml>" -Dlog4j.debug

The last three params are for log4j and they are my problem

I have log4j jars in classpath

lax.class.path=<other jars>;log4j-1.2.17.jar

But nothing comes up, there is no log and no java process. What could be missing here?