We have two servers:
- Server1: MOSS 2007 content with ESP web parts
- Server2: SP 2010 acting as query server
We need to crawl the Server1 content from Server2, and installed ESP web parts on Server1 need to refer to Server2 as the query server. So user queries from MOSS 2007 go to the SP2010 box (where content is crawled) and return the result on the MOSS 2007 server.