Joined: 26 Apr 2004 Posts: 4652 Location: Raleigh, NC, USA
Use reverse-engineering.
Create the spreadsheet data in the desired text-based format, then upload that data to the mainframe. Now, you'll know how you need to format your data (and yes, you have to write the code to do the formatting). Some common data-exchange formats are comma-separated, tab-separated, symbolic link, HTML, and XML.
If you use XML for the data format on both ends it won't required any formatting conversion.