PDF to HTML Conversion with Interapplication Communication Api in Mac OS

I'm trying to convert a PDF file via the Interapplication Communication API of Adobe Acrobat.

My script doesn't appear to be converting my file from PDF to HTML.  It works for other formats (e.g. plain-text).   Here is my AppleScript code:

set myfile to "/PATH/pdf_schedule.pdf"

set outfile to ("PATH:pdf_schedule.html" as text)

tell application "Adobe Acrobat"

  -- get every conversion

  activate

  open myfile

  save document 1 to file outfile using conversion "com.adobe.acrobat.html"

  close document 1

end tell

And `get every conversion` returns this:

{EPS Conversion "com.adobe.acrobat.eps" of application "Adobe Acrobat", conversion "com.adobe.acrobat.xlsx" of application "Adobe Acrobat", conversion "com.adobe.acrobat.html" of application "Adobe Acrobat", conversion "com.adobe.acrobat.jpeg" of application "Adobe Acrobat", conversion "com.adobe.acrobat.jp2k" of application "Adobe Acrobat", conversion "com.callas.preflight.pdfa" of application "Adobe Acrobat", conversion "com.callas.preflight.pdfe" of application "Adobe Acrobat", conversion "com.callas.preflight.pdfx" of application "Adobe Acrobat", conversion "com.adobe.acrobat.png" of application "Adobe Acrobat", PostScript Conversion "com.adobe.acrobat.ps" of application "Adobe Acrobat", conversion "com.adobe.acrobat.pptx" of application "Adobe Acrobat", conversion "com.adobe.acrobat.rtf" of application "Adobe Acrobat", conversion "com.adobe.acrobat.accesstext" of application "Adobe Acrobat", conversion "com.adobe.acrobat.plain-text" of application "Adobe Acrobat", conversion "com.adobe.acrobat.tiff" of application "Adobe Acrobat", conversion "com.adobe.acrobat.doc" of application "Adobe Acrobat", conversion "com.adobe.acrobat.docx" of application "Adobe Acrobat", conversion "com.adobe.acrobat.xml-1-00" of application "Adobe Acrobat", conversion "com.adobe.acrobat.spreadsheet" of application "Adobe Acrobat"}