Maybe you should try to use to use other version of PDF Metamorphosis .Net ...
See here:
http://www.sautinsoft.net/help/rtf-html-to-pdf-split-merge-net/Overview/history.htm
"5.3.7.11 - July 11th, 2011
We are happy to offer the new PDF Metamorphosis .Net 5.3.7.11. What's new:
Added support of new CSS: 'vertical-align:'
Improved working
with borders, background, vertical alignment in HTML tables
Fixed issues with styles: 'page-break-after', 'page-break-before' and 'page-break-inside'
Description of all methods and properties in documentation enhanced by pictures, like this
...
5.2.11.22 - November 22th, 2010. We are glad to offer new version of the PDF Metamorphosis .Net with new usefull RTF to PDF features and fixes:
Added support of new table border'
s types: dashed, dotted and double.
Compressed and expanded text in produced PDF"
Good luck.
Alex.