How do I replace a bump stop cup and where to find the part?

What is your question?

I have a 2006 Chevy Express Van. The back passenger side bump stop has fallen off. The problem is the cup the stop is inserted in is gone as well. I tried the dealer ship as well as auto parts stores and looked online. I cannot find a Bump Stop Cup anywhere. It looks like the cup was originally welded on. Any suggestions for a replacement part. I want to install the Timbren suspension enhancement system due to being a work van but I have no way of attaching without the cup.

What makes this problem better or worse?

Part is missing.

How long has your 2006 Chevrolet Express 1500 had this problem?

Just noticed the cup was missing.