Data Base Extensions

Hi,
I did my core data base extensions while at Las Vegas recently.
I haven't attempted to do my custom fields yet, because I'm inundated with 'pre-school opening' tasks & state reporting.
I have however, noticed that I'm having issues with the core field that used to be called 'guardianship' but is now called 'StudentCoreFields.guardianship'.
I had created a Registration page (a kind of a 1 stop shopping page of the necessary demographic fields for registering a student). The guardianship field resides on the student demographics page, with the field name 'guardianship'. I also included this field 'guardianship', on my custom Registration page and when the guardianship field was populated on either the Registration page or the demographics page, it auto populated the guardianship field on the 'other' page. Now, however, the field does NOT auto populate on the 'other' page.
Also, when I do a list student & pull 'guardianship', I get results (from the demographics page, 'guardianship' field. Nothing currently resides in the 'guardianship' field on the Registration page. When I do a list & pull 'StudentCoreFields.guardianship', nothing results.
I do not want to lose the data that resides in the old 'guardianship' field, but I would like to also have this data reside on my custom Registration page.
How can I accomplish this?
Thank you,
Nancy
ps. I took the DataBase extension classes, Beginning & Advanced, in Las Vegas, but I'm lost as to how to correct this, as I thought the data would 'stick' with the new naming convention?