Per module compiler settings?

Hi,
I'm working on a Java ME project. One module contains the application sources (Java 1.4 level). Another module contains the test sources (Junit4, Java 6 level).

I had to set the compiler's command line to compile for 1.4 (-target 1.4) so that I can deploy the app on Java ME devices. I did this in the settings dialog (project settings->Compiler->Java compiler).

How can I now use different compiler options for the test module?
It has to compile for Java 5 or 6 because I want to use JUnit4.