I don't know if this is helpful, but from the FM12 Help file:
Home > Using FileMaker Pro > FileMaker Pro basics > New features in FileMaker Pro 12
>Changed and removed features
>>Features changed in FileMaker Pro
"Importing data from FileMaker Pro databases - Import order has been improved. The addition or deletion of fields after field mapping no longer affects the sort order in import target files."
Maybe this is only good for FMPro<-->FMPro?
-- Drew Tenenholz
What is the format of the file containing the information you are importing?
If you could format your input file as a CSV with the first line containing the field names, the rest of the lines the data, you could select
"Matching Field Names" as your import Order, then if you delete one of the source fields from the import file, you will not change the import
order of the remaining fields.
I should have been more specific, I am importing from another FMPro database.
Drew, I'll have to try it with FMPro 12. That would make things a lot easier when setting these things up if that is in fact the case.