Well I dont know how it was saved in the database using the old system so I can't really say. You can post an example here of how the old style is stored in the database and I might be able to assist
There is one correction I posted above that I would suggest in displaying html as convert_markups can not be on the line to allow html as it will mess with it so lines 323-325 of showproduct.php should be this
Code:
Content visible to verified customers only.