Here is a video: How to shorten Miu Miu Strap...although it's a bow in the video I think the straps should be the same for vitello lux? you have to tug a bit for the little circle leather piece that goes around the two straps lol I'm sure I'm making no sense like this! the video is very helpful.
follow the pictures in this link to remove the gold hardware from your straps. the gold hardware prevents your strap from being inserted into the loop.
these pictures also show a second method of shortening a straps by simply removing the hardware all together and just attaching the leather straight to the loops.
I think for the vitello shopper, you have an easier option of going UNDERNEATH the ring. If you catch my drift, thats what i do. Else it'll be a hassle switching btw messenger style and shortened strap..
For the bow i'm not sure if that can be done, as i dun own one.. Lol. Yet.
I used the method as on the video. That was also what the SA showed me. You have to remove the hardware before letting the strap goes through the ring.
Really? I think if you force it a bit, it comes out, it's probably because your bag is very new, but trust me, it works I am constantly putting and removing, and folding my strap on my Bow, and it's all good. It becomes easier and easier with time.