We need more information if we are to help you. Are you referring to an XML element named <argument/>, or a paragraph format named 'argument'?
For the XML case, I would use an XSLT style sheet to generate the required structure on import and an equivalent style sheet to deconstruct the table structure on export. This has to be accompanied by a DTD and EDD to define the table structure inside FrameMaker along with read/write rules to identify the various table parts. If this is an XML problem, which DTD or Schema are you using?
For the unstructured case, ExtendScript will be the best way to achieve your aims.
We can provide more help once you let us know which case matches your requirements.