Importing Custom Records to Employee Records

All,

    I am attempting to import some custom records. I need these custom records to attach to the correct employee records when importing. I would like to do this via Internal ID of the employee record rather than the actual employee name, but I can't seem to figure out how to do this. On import, I am selecting "Custom Record', My custom record, Add, then more or less the default options. However, I am unsure how to get the import wizard to look at the internal ID of the employee record for import. Essentially, on the custom record I have