I have a document library that also needs to include the Record#.  The Record# is created in the Change Requests list, so I thought I would create a column called Ref in this Document Library that looks up the values in the Record# column of MyList.

While creating the document library Ref column, I chose the information type of Lookup.  In the Additional Column Settings block, I selected the Change Requests list in the "Get information from:" drop down list.  The problem is, when I next browse the "In this column:" drop down list, The Record# column is not displayed, so I can't select it.

What is the secret for getting a site column that I create to appear in the column drop down list for a lookup column?