DB_DO_FormBuilder to create data range search

Hello, I started to implement some code to display a DB table with Datagrid and I used QuickForm to let the user define data range for its search. For instance, this allows him to define ranges for integer and date fields. Then I found the wonderful FormBuilder package and started to play with it. Unfortunately it can't create off the shelf such range inputs. So I wonder if there is already something available. And if not, what is the best way to insert my extended QF elements. I know there is the FB elementTypeMap, but I can't find where it links to the rest of FB. Thanks for your suggestions. -- Michel