Bitronix + Spring tests + Different spring profiles

I have several tests which all extends the same root test which define the Spring test application context. One of my test use a different profile so I have annotated the child class with @ActiveProfiles("specialTestProfile"), this profile create a special mock bean which is injected in the context. I want to clear my context before and after executing this test, but I didn't find the correct way to do it. I know that the Spring test framework does some context caching and that in my case I should have two different context and it should not be necessary to reload the context but it is not working because of bitronix which generate this strange error if I don't clean the context:

    Caused by: bitronix.tm.resource.ResourceConfigurationException: cannot create JDBC datasource named unittestdb
    at bitronix.tm.resource.jdbc.PoolingDataSource.init(PoolingDataSource.java:57)
    at sun.reflect.GeneratedMethodAccessor404.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeCustomInitMethod(AbstractAutowireCapableBeanFactory.java:1608)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1549)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1479)
    ... 62 more
Caused by: java.lang.IllegalArgumentException: resource with uniqueName 'unittestdb' has already been registered
    at bitronix.tm.resource.ResourceRegistrar.register(ResourceRegistrar.java:55)
    at bitronix.tm.resource.jdbc.PoolingDataSource.buildXAPool(PoolingDataSource.java:68)
at bitronix.tm.resource.jdbc.PoolingDataSource.init(PoolingDataSource.java:53)
... 68 more

Even if I reload the context for each test class (by annotating my parent class with '@DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_CLASS)', I still get the error above at some point... do you have any idea how to solve this problem?