Why is the through axle adapter T2835 not available any more?

Hi, I want to use my bike with a 148x12 axle on my Tacx Flux. However I cannot find a shop, that sells the adapter T2835. Even in the official Tacx store it is not available any more. How can I get one or ehat can i do about hit issue? i cannot use my trainer any more with my new bike. 
Are there any instructions for a diy solution?