Message Title

I've to map several tables in a single java bean (1:1); each table share the same foreign-key ('sessionId', an UUID) which is not the primary key (a bigint); so I've tried the following mapping with hibernate 5.0.5.Final:

  <class
      name="beans.NeutralTable"
      table="MeasurementSession"
  >
      <id column="#id" name="longId" type="long"/>
      <property column="@creationtimestamp" name="date1" type="timestamp" />
      <property column="sessionId" name="textId" type="string" not-null="true" />
      <join
          table="ComputationDone"
          fetch="join"
          optional="true"
      >
          <key column="sessionId" foreign-key="sessionId" property-ref="textId" not-null="true"/>
          <property column="keyData.Isc" name="floating1" type="double" not-null="false"/>
      </join>

  </class>

Whatever I put on the 'foreign-key' and 'property-ref', hibernate always try to join on the primary key (#id):

2015-12-14 10:29:14 CET ERROR:  operator does not exist: bigint = text at character 338
2015-12-14 10:29:14 CET HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.
2015-12-14 10:29:14 CET STATEMENT:  select neutraltab0_."#id" as column1_1_0_, neutraltab0_."@creationtimestamp" as column2_1_0_, neutraltab0_."sessionId" as sessionI3_1_0_, neutraltab0_1_."keyData.Isc" as keyData2_0_0_, from "MeasurementSession" neutraltab0_ left outer join "ComputationDone" neutraltab0_1_ on neutraltab0_."#id"=neutraltab0_1_."sessionId" where neutraltab0_."#id"=$1