The clarinet sroce is wrote in Ut, it's the same armature (2 sharp). It's means, if you want to play in Sib, you just need to transpose with 1 tone upper.
I like the arrangement very much, but play Bb clarinet and do not no how to transpose the mib. I don't know what an mib clarinet is. I really like the contrast between the instruments.
SHEET MUSIC