NC Drill Problem

I've recently completed a design on a new PCB and I've done two things I haven't done so far with PCB Designer.  The first was to mount a component at an odd angle (13 degrees).  This worked well.  This component also has two non plated slots for alignment pins on the component.  I created the non-plated slots using Pad Designer and incorporated the slots into my package symbol as a mechanical element.  Here's where I'm running into a problem -

 I can see the slots on the board when looking at it in PCB Designer 16.5.  I can toggle the holes on and off on the screen, and the slots even show up on the 3D view of the PCB.  The slots and their respective symbol show up on the Drill Legend and they are included in the hole count, but, when I generate the NC Drill file, the slots aren't showing up.  I missed it at first, but the PCB fabricator sent me an email and wanted to know what to do with the oval-shaped spots in the solder mask, because there was no NC Drill data for that area.  Sure enough, I opened up the drill data using Pentalogix Viewmate, and the slots are not there.   The board fab place is going to manually put the slots in for my prototypes, so I'm OK for right now, but for production boards, I'm going to need this data to be present.

 I'm probably missing some setting in the drill parameters or something, but I have no idea what it is.  Has anybody else run into this?  Does anybody have any idea what I'm doing wrong?  I've tried changing a few settings in the NC Parameters, but so far, nothing I've tried has worked.