[AccessD] Automating Excel imports

My client needs to frequently import batches of customer data into the CRM
database I built for them in A2007. I created an Excel template which they
use to supply the data, and I have an automated process that reads in the
batch and loads the database. This is the command I use to do the import:

DoCmd.TransferSpreadsheet acImport, acSpreadsheetTypeExcel9, BatchTable,
Import_File, True, CellRange

All of the fields in BatchTable have a data type of 'text'.  The problem I'm
running into is that TransferSpreadsheet barfs if any of the zipcodes in the
spreadsheet are formatted as numbers. Before A2007 I used to use an Import
Spec, which would circumvent this problem. For some unfathomable reason,
this feature no longer exists (that I know of). If this was a one-time
import I could deal with it by manually importing into a new table and then
copying the data into BatchTable, but this is a recurring event.

Any advice on how to deal with this issue?