Bart,
You add parameters to the Integration Server’s JVM by editing the server.bat or server.sh scripts found in the Integration Server\bin folder.
The changes shown in my quote above are for the server.bat file. If your are using Unix, you will need slightly different syntax to set or to use the environment variables JAVA_RUN, JAVA_EXE and JAVA_MEMSET. Your friendly Unix sysadmin can help if this is not something you are familiar with.
Mark