Detailed Sales Report and Items w/o dept filters

When my customer enters new items they sometimes forget to assign a department to the new items. When they run the detailed sales report with just changing the dates everything is fine all dept (and items sold w/o a dept are shown too). However, I need them to filter out a few departments on the detailed sales report. When they create a filter (example department "shoes") Then it also filters out the items sold that don't have a dept assigned to them, thus the sales amounts for those items are not counted and the sales report is not accurate. What can I change on the report so that it will filter out certain departments but not filter out the items where department is not set? Something like an OR statement or better yet if sql finds an item w/o a dept it will display the dept heading as "No dept" and show on my report? This has to be a HUGE bug in the report and I am suprised that no one has posted or a fix for it yet. There has be the many people that add new items w/o depts, and if they filter departments on detailed sales, then these items are also filtered out and not counted in sales! Thanks in advance.