Thanks Xendula - glad you like it!
It a standard 22mm deployment clasp - you will find them easily either on ebay or here (good if you are in the EU), although I can't see the clasp by itself but at least you get a spare strap to practice with:
Watch band He-KB10 22mm silicone deployant clasp
Now, the bit you need guts and and a drill press (or milling machine) for is coring (not drilling) a 1.2mm hole in the band and then cutting it to size. Removing the band is straightforward with a T5 torx to mount it in the milling vice. I made my own coring tool from some mini copper tube I had in stock on the lathe. I then practiced on a spare rubber strap I had until I was happy with the technique and drill speeds etc. I used washing up detergent (Fairy Liquid) as a lubricant and it worked a treat:
Needless to say your warranty is void (at least for the strap) if you decide to do it but I think it really transforms the watch, and given that machining is another hobby of mine I was happy to give it a go.....