[Greasemonkey] Button for Smiley Xtra in Rich-Text Editor Toolbar

[WHITEMARE2]

I wrote a Greasemonkey script that creates a rich text editor.  It is used at several forum sites.  People have asked if it would be possible to add a button to the editor toolbar that will allow them to choose a smiley from the Smiley Xtra extension.  Smiley Xtra already works well with the editor, so the issue is adding the button.  Is it possible for a Greasemonkey script to launch an extension?

thanks!