I am using a Views PHP field in a Services View. The field name in the output of the service looks like this, views_php_14. I don't seem to be able to change this a field name of my choice.

This field is the 15th field in the view. If I remove one of the earlier fields, the name changes to views_php_13. The number at the end of the name must be the number of the field (starting from 0).

Can the name of the field be controlled? And constant?