The column name <col> was not found in this ResultSet

Hello,

In a query like this:
select * form T1 a, T2 b where a.id='xx' and a.id=b.id

calling the result set:
rs.getString("o.id")

I get:
org.postgresql.util.PSQLException: The column name o.id was not found
in this ResultSet. at
org.postgresql.jdbc2.AbstractJdbc2ResultSet.findColumn(AbstractJdbc2ResultSet.java:2562)
at
org.postgresql.jdbc2.AbstractJdbc2ResultSet.getString(AbstractJdbc2ResultSet.java:2405)
at
hu.prolan.emgmt.fre.service.store.impl.OrderStoreImpl.loadOrder(OrderStoreImpl.java:236)

Getting data by index is OK, just as simply using getString('id'). This
nonqualified access however cannot get to the next column with the
same name...

How can the columns accessed by qualified name?
Is it a bug?

I use:
postgresql-9.1-901.jdbc4.jar
openjdk6

Please cc to me as I am not on the list!
Thanks!

Zsolt