Problems with Find method in EJB

[Nick15]

Hello everybody:
I have a problem and I still could not have solved it
I have my bbdd with fields, this fields are varchar type and char.
My problem is with char type and finder methods.
If I have, for example, a field with (char(10)) and I do a EJBQL like this

<query>
<query-method>
<method-name>findByMiBusqueda</method-name>
<method-params>
<method-param>java.lang.String</method-param>
<method-param>java.lang.String</method-param>
</method-params>
</query-method>
<ejb-ql>
<![CDATA[select object(o) from MYEJB o WHERE (o.cod1 = ?1 ) AND (o.cod2 = 
?2) ]]>
</ejb-ql>
</query>

If the field 2 has this type, never returns me results, if I change the type to a string, it does not happen.
can you help me?
nicholas