Following his example, tried with the following condition and got success:
[ISAPI_Rewrite]
# Bloquear acesso aos arquivos "httpd.ini", "httpd.parse.errors" e ao help
RewriteRule /httpd(?:\.ini|\.parse\.errors) / [F,I,O]
RewriteRule .*\.isrwhlp / [F,I,O]
RewriteRule ^(.*)/$ /index.php/$1 [L]
Bye.
