We have a form for departmental transfers of bank data....

Dept/Account/Amount/Date/Description/etc etc etc

Our accounting system can accept file feeds on the mainframe in text format.  So if I could export form variable data at a text file that I could feed to the accounting system via ftp to the mainframe we could automate departmental financial transactions in our accounting system.

I think I understand what you are trying to do.  So, after the form is in complete, you would like a file created that has the data in it that was put into the form?  I assume, this can be done after the form process is complete. 

We deal mainly with Credit Unions, but the processes are typically the same.    Is there typically a specific file type that needs to be used to upload to the mainframe?

If my assumptions are correct, I would do the following:

1. Complete Form
2. Use service task to envoke a workflow process.
3. The workflow will take the form data it is passed
4. The Workflow will output the form data to a CSV file via an ODBC connection and enterprise insert data activities.

This is now a text file as a csv spreadsheet.  If any other formatting is necessary, then I would email the plain text to myself, since the email formatting can be adjusted in the email activity.  Then I would copy the text from the email and save as a txt file or whatever text file is needed for your mainframe. 

Hopefully that makes sense.