How to prevent losing named range functionality when adding encryption?

[CassEK]

I need to add a password to an Excel 2007 workbook that uses dozens of named ranges. When I add the encryption, the named ranges lose their references and return the #NA error. I have tried to re-establish the referenced ranges in the Name Manager by reselecting but once I save and reopen the workbook they are lost again. Has anyone else had this problem? I can't find anything similar to it