On a form data source, you can set default values by overriding the initValue() method. If I set all the fields to a default value, it will not save. AX sees that this line is unmodified by the user and therefore will not save it. If a field is manually changed from the default, then it inserts the record into the table successfully.

Is there a way to flag the current record as modified so that AX attempts to save it as if the line was entered manually?

If it makes a difference, the data is presented on a grid control.