I had a similar issue with RAD 8.5 and WAS 6.1 and in my case I had to edit the server.xml
It is located in : [WEBSPHERE_HOME]\AppServer\profiles\config\cells[NodeCellName]Node01Cell\nodes[NodeName]Node01\servers\server1\server.xml
Look for the tag: < jvmEntries /> This tag has few attributes like @debugArgs, @genericJvmArguments make sure that you have the arguments you need.
Hope that helps you.