ISAPI_Rewrite from Helicon is simply mod_rewrite in Apache equivalent. In order to use caching you'd need HeliconApe, which includes ISAPI_Rewrite functionality along with all the bells and whistles of Apache. Make sure your provider has HeliconApe, not just ISAPI_Rewrite3.
Yes, you can make a file from scratch, but I'd suggest referring to their official site for correct syntax.