IHTMLTxtRange.findText method returning false

[cvk]

Hi
the IHTMLTxtRange.findText method is returning false when the search string contains the character '&', '[', and ']'. i tried to replace the & charcter with & and  &. even then the find method is returning false.
if the search text does not contain any special characters the find method is returning true.
can anyone help me to know what is the issue and how to resolve it