What is a “tip jar”?
Is this something just on the home page? Sidebar? Just part of an article?
My opinion is that if this is part of the structure of the site, you probably want to get it into the template, which exists as data dynamically rendered into the page. I think FrontPage might be useful to create something WYSIWYG as a separate file and then paste it in, but Front Page can’t “reach in” to the database to edit the code as it exists there.
Also, the templates are a mix of HTML, script, PHP, and some Word Press specific things. FrontPage is not going to recognize all this stuff, so you need to be prepared for this.
FrontPage is a great little tool for simple things, but it is Microsoft centric and has a reputation for changing code as it saves things. Because of this, most people move away from this as they get into more serious projects.