Websphere 7 Classloader issue WSPreLauncher not found

I'm using IntelliJ 10.5.1 and Websphere 7 installed locally.

I've created a new run configuration for Websphere which runs ok but does not work when I try to run in debug.

I get a ClassNotFoundException within the URLClassloader. It can't find 'com.ibm.wsspi.bootstrap.WSPreLauncher'.

I've looked for this class and it resides within the Websphere bootstrap.jar ({WebsphereHOME}/lib)

I've tried attaching this class to the Websphere run configuration but that doesn't help.

As I said above, if I run the configuration without the default debug jvm arguments there is no issue. Any help would be appreciated