I suggest to replace the syntax description
StringReplace ( "string", "searchstring/start", "replacestring" [, occurrence = 0 [, casesense = 0]] )
with
StringReplace ( "string", "searchstring"/start, "replacestring" [, occurrence = 0 [, casesense = 0]] )
This makes clear that parameter 2 is either a string to search for or an integer to be used as the starting position.