how to workitem Queries/mass edits with custom text fields

we have added some text fields to our defect workitems..

now we would like to USE that field in queries, reports and mass workitem edits..

as an example

1. we would like to list all the workitems where xxx is empty
2. the reverse.. list all workitems where xxx is NOT empty
3. list workitems where xxx starts with '132'

then in the case of bulk edit, in the workitem list, you can change a field on a group of workitems which you can multi-select.. but you cannot even display the custom field as part of the query results..
as an example.. I need to change the assignment for all workitems where xxx= 345u7.. there could be 1 or hundreds..

Sam