Dozer - mapping problem

Question

We have two beans Source and Destination with the same properties :

private Map<String,List<Tarif>> tarifBySegmentAndByPassenger = 
    new HashMap<String, List<Tarif>>();

Every works "fine" except in the Destination bean, all the Tarif object has been replaced by something like this : com.mypackage.Tarif@2453

Dozer seems to do a toString conversion (??!!!)

We have tried to create a CustomConverter to solve the problem but, this time, the Source value object is always null ...

<mapping>
        <class-a>com.mypackage.Source</class-a>
        <class-b>com.mypackage.Destination</class-b>
        <field custom-converter="com.vsct.rd.conceptcar.core.utils.CustomTarifsBySegmentAndPassangerConverter">
            <a>tarifBySegmentAndByPassenger </a>
            <b>tarifBySegmentAndByPassenger </b>
        </field>
    </mapping>

Stuck again .. do you have any idea for one of the problem ?