FrontPage is like AOL .. they would have you believe theirs is the only way.
You can write an .htaccess and upload it through a seperate FTP client, with no reference to FP. But ... I don;t know what FP server extensions do; it may well be that they do interfere.
I would advise you to abandon FrontPage - it is the dark side. If you really want that kind of workspace and editor, try Dreamweaver, which is far more in tune with reality