end user has a section of their XML data like so in datamapper:
@datatype = decimal
@fieldName = oeeh.Amount
0.00
@datatype = decimal
@fieldName = totlineamount
251.52
…
Is there any way to extract the @fieldName attributes and use them in a loop to name each new extraction field?
Nope, that would go against the core principle of the datamodel: providing a uniform, consistent set of fields. What you can do, however, is store the Name and Value as two separate fields in a Detail table. You will then be able to loop through that table in your template.