Go down to your local vacuum shop and see if they carry a Style ST over-mold kit. Or if you're part of this trend of "Home Shoppers", I've found a link below for the complete conversion kit, at a modest price of $10.

While you await your shiny new Conversion Kit to show-up at your door, go ahead and remove the F&G bag, and the bag itself. toss the disposable bag in the trash, And lightly wash the bag in a sink (Laundry sink works best, Kitchen sink none the less) with some dish detergent. Let the bag dry (You can speed this if you really want to by running the machine with no paper bag, just don't vacuum anything! )

When your conversion kit arrives, you will simply slide the rubber mold of the conversion kit on to the fill tube (Where your F&G bag could normally connect) and attach it with the spring. Be sure you install the fill tube so the exhaust (Or where you attach the bag) is facing the zipper of the bag. You can now buy and use HEPA Sanitare Style ST bags! Hooray!

Special Thanks to User DURANGO159 for the link!