As far as I can tell, the touchup text tool does not work in PDF Converter Professional 7.0. I tried it on a PDF document. It highlighted text. But none of the features (such as inserting characters, deleting characters) had any effect.
The workaround I came up with was to use PDF Converter to convert to a Word document. Then I could change a zero to a one. Then I converted back to PDF.
It is a shame that this feature does not work. Maybe it will work in PDF Converter Professional 8.0?
