[Plugin: NextGEN Gallery] Add Flashvars to Shortcode?

I want to control NextGen slideshows using flashvars for two reasons:
1: To have control over the image rotator flashvars (http://developer.longtailvideo.com/trac/wiki/Flashvars3) that NextGen doesn’t offer in its options.
2: To have some slideshows behave differently from other slideshows on the same site.

Specifically, I want to get rid of the fullscreen button on the controlbar.

How can I do this? Following the shortcode shown here http://nextgen.boelinger.com/slideshow/, I hoped I could do this:
[slideshow id=3 usefullscreen=false] but it doesn’t work.

Can I control flashvars in the shortcode? If not how do I use flashvars with NextGen Gallery? Specific examples would be great.

Thanks!