how do you convert magdura mounts to v-brake

the title

btw the adaptors look like this

thanks, I see that your a UK man so hopefully someone else knows where to get them in the US

http://www.trialsin.com/sell/pieces/pframe.htm

go to Brake Parts and Accessories

thanks, anyone found a cheaper version, as these are $45

make your own for like 5$

and how would you do that?

something like