When using SmartConnect to import into an eXtender window, any string fields that are blank or null in the source file show up as 0 in the actual eXtender window after the import.
This will be resolved in the next release of SmartConnect. Currently to correct the issue you need to run this SQL script against all your company databases. After running the script, the procedure will be changed so it does not insert anything into a string field if the source field is null or blank. You can download the SQL query here