file text replace

hello, i have been trying to replace an automatically generated text from a html file so far this is what i have found

$fileopen = FileOpen("vol002.htm", 1)
$sNewText = StringRegExpReplace($fileopen, "[<!-- generated -->]", "this try")FileWrite($fileopen, $sNewText)
FileClose($fileopen)

i belive i have to rewrite all the document replacing <!-- generated --> to this try then use filewrite but i cant find how to do that