This exact repair was done by Janne Jarvinen (Finland), his video here should give an idea the amount of work to fabricate the part...
https://www.youtube.com/watch?v=eGt4XUQ3Wg4
He has a thread on Allmetalshaping covering same, but you'll need to be member on that site to see the uploaded pictures..
http://www.allmetalshaping.com/showthread.php?t=15010