How to add this JS to a new button?

Hi guys. I have a question. I need to add a one more button to FCKeditor panel.
I used BUEditor for Drupal before, now i want to use FCKeditor. So, what would be look like the code for a fckplugin.js file if in BUEditor i had this:

js:
 
myUserInput = function(form) {
  E.replaceSelection('<a href="http://example.com/download.php?filename='+ form.elements["filename"].value + '&path=' +
form.elements["path"].value + '">' +
form.elements["title"].value + '</a>');
  editor.dialog.close();
}
 
var html = 'Filename: '+ eDefInputText('filename') + '<br/>';
html += 'Link href: '+ eDefInputText('path') + '<br/>';
html += 'Title: '+ eDefInputText('title') + '<br/>';
html += eDefInputSubmit('sbmt', 'OK');
html = eDefHTML('form', html, {onsubmit: 'myUserInput(this); return false;'});

editor.dialog.open('File', html);