I have always seen tzitzit attached to a garment via a hole (or two holes) through which it is "laced" through and tied.
Is this the only allowable method? Can tzitzit be attached by using a staple, or sewn into the garment using thread (without the big hole) or using Velcro or some other method?
An example, of attaching - Fold the bundle in half (like you do using the hole) with each half hanging over the corner of the garment. Use a thread or staple to attach the two half corners, and then start the twists and knots from that point.