Filtering with float fields

Hi,
 
I am trying to apply a filter to a container in a field defined as Float. I
have only found how to add a RangeClause to a ContainerFilterBean in the
case of string and date, but not Float.
 
I am working with Jahia 4.0.5. and this is the source code for the
filtering:
 
    myContainerFilter = new ContainerFilterBean("aFloatField", true,
jParams.getEntryLoadRequest()); // with the field name
    // Adding equality comparison with selected values
    myContainerFilter.addRangeClause(">","<",valueFrom,valueTo);
 
This filtering always returns 0 element found, because only String values
are allowed for the fields valueFrom and valueTo.
 
Thank you for your helping.
 
Cheers.
 
Alex.