Hi Syd and thanks for posting!
I don't know the answer to your question, but one possible workaround would be to just convert your form to regular XML and map that to SQL using a Web service (such as DBXL). You'll have more control over your form's data that way. However, I realize that's a major change though.
So, some other ideas: from the File menu in the InfoPath Designer you can export the form as source files and look at the XSD file that was "inferred" from the SQL database. Open this up and look at the SSMA field. Say you want to change it, you can open up the manifest.xsf in notepad and change the edit mode properties for the XSD to be "Full" (or something like that). To resave the XSN, just save the manifest.xsf file (make sure the InfoPath Designer is closed first) and then right click and choose Design. Then you can see if your change allowed you to update the data source. You can also open up the XSD in notepad and manually modify it, but I'm not sure that submit will succeed if the type data is incorrect. Might be easier just to auto-fill the field with the value that it wants. What is the data type for the SQL SSMA field? Maybe InfoPath just doesn't know how to convert to that.
Good luck,
P