Set a jaxb:javaType to a part of composite keys make the IdClass attribute as String

Hello,

This is a strange behaviors with Hyperjaxb ( tested with 0.5.6 and latest ).

If i specify a javaType (with parse and print method) to an attribute which is a part a composite key, then hyperjaxb create an IdClass (ok, composed with all keys attributes) but with the attribute typed as String ( and not Date as the following example ).

```

```

Results :

```
@XmlAccessorType(XmlAccessType.FIELD)
public static class TickerId {

@XmlSchemaType(name = "dateTime")
protected String timestamp; // Should be a Date there !!
protected String currency; // Other part of the composite key, that's ok
...
}
```

If i remove the binding an XMLGregorianCalendar is generated (i don't want this), moreover a parse exception is throwed. That's normal because the string date format found is not recognized as the standard date format.