Hibernate seems not to resolve alias correctly - oracle

Question

since some days I'm facing the following problem:
I am using Hibernate to do the following Restriction on a criteria:
...
criteria.add(Restrictions.sqlRestriction("1=1 CONNECT BY PRIOR {ProcessEntityworkflowProject}.ID = {ProcessEntityworkflowProject}.PARENT_ID"))
Where "ProcessEntityworkflowProject" is the alias which should be resolved by hibernate.
This alias is set in code properly. I also debugged the code and inspected criteria:
There I could see that a subcriteria in subcriterialist of criteria has this correct alias bound to the association path.
But in SQL logs I see that it is not resolved:
... and this_.EXTERNAL_KEY is not null and 1=1 CONNECT BY PRIOR {ProcessEntityworkflowProject}.ID = {ProcessEntityworkflowProject}.PARENT_ID and processent4_.TYPE_ID=? ...
... or is this output correct and it is resolved later internally?
And in tomcat.log I see that there is a NPE:
java.lang.NullPointerException
at oracle.jdbc.driver.T4C8Oall.getNumRows(T4C8Oall.java:876)
at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:831)
at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1039)
at oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:850)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1134)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3339)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3384)
at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:92)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:139)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1669)
at org.hibernate.loader.Loader.doQuery(Loader.java:662)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.doList(Loader.java:2145)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
at org.hibernate.loader.Loader.list(Loader.java:2024)
at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1533)
at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:295)
I already found out that this NPE is cause because Oracle JDBC driver can not parse the brackets "{" "}". So I guess that the alias was not resolved properly.
Does anyone of you have an idea what could be wrong or how I could investigate deeper?
Some additional info:
I am using Hibernate 3.2.0 (CR1 afaik), tomcat 5.5, ojdbc14.jar.
Running on RHEL 6.4 and Oracle 11g
Many thx in advance if some of you have an idea ;)
Cheers
Sascha