How to carry a large fabric lens cap

I recently acquired a 400 DO. Tougher to get this lens cap into your pocket. I also have 1.4 and 2X TC. Before Art Morris jumped ship he suggested in a video to lock them together with a extension tube and keep them in a pouch. You can get a cheap one on Amazon. I got a 12mm tube and a Lowepro 8 by 12 cm case. Fits like a glove.

First time out last week with the new case I noticed that the cap fight right over it. I stitched a piece of velcro to the case to keep the cap there. Very convenient now. The cap fits 4 types of Canon lenses.