.txt file posting has nothing to do with multiple categories. Directory posting in described here:
http://poster.themasoftware.com/faq.php?expand=faq407For multiple categories you need add this line anywhere in your message text:
Code:
<categories>Section 2, Section 3, etc.</categories>
Where "Section 2, Section 3" are section names which are added in themaPoster (basically which you have in "CONFIG" -> "Template's sections"). Template with needed ID must be added for those sections.
You can add that line in themaCreator "Main" template.
Take a look at your section names in themaPoster -> "CONFIG" -> "Template's sections". Write needed sections. Section = Category for Wordpress.
Just try it.