If you really have your heart set on a button I would try the .hta approach. When the user double clicks on it, it opens just like a text file opens the default editor.
Only it's considered an "application" on the system. You can read more here: Introduction to HTML Applications (HTAs)
edit: the wysiwyg editor does get stuff on a page quickly. But looking at it afterwards is the tough part. They tend to stick a zillion " "s in the page to space things. But look around. You may find a free HTA "toolkit" on the web someplace.