sleeve with thumb

Awfully quiet here nowadays... And I must say that I am one of the guilty ones, Colchique hasn't been much worked on lately. The reason is- I'm stuck! I am working the pattern in Dutch (which I don't speak), and I want to make the sleeve with the thumb thing, which is one of the really cool things about this sweater in my opinion. But the dutch description is really hard to understand and I am stuck. I have contacted a dutch blogger who agreed to help, but haven't heard from her. Anyone else working the sleeve with thumb, who can help me?

The four major pieces are complete. The thought of the collar has frozen me in time. Has anyone done it yet? And attached it? The other color bit - if the purpose is to have live stitches, can I just put them on a holder instead? I need help to get over this hump otherwise this sweater will never see the light of day!

UPDATE: The additional button piece - it'll attach to the front along the left arm area, right? As I was working on it it seemed a little long - does it continue up and attach to the collar, too?