Actionscript :: Get A Smooth Text Crawl Using Flex?

I'm working on a standalone Flash application (written using Flex 3/ActionScript 3) that features a text crawl, like what you might see at the bottom of your TV when watching a cable news channel; it's a long narrow box that text moves across from right to left. I've implemented it by creating a Label element, populating it with text, and then moving it using a mx:Move object with a Linear.easeNone easing function. It works, but it has ample room for improvement. It looks a bit jerky, and tends to have a fair amount of "tearing" (the top and bottom halves of the text sometimes fall out of sync).

I tried throwing math at the problem to get the crawl's movement rate synced with the monitor's refresh rate, but that was a bust. I found out the hard way that the app's frame rate jumps around too much; the "optimized" crawl varied between looking silky smooth and like it had epilepsy.

Is there anything else folks would recommend I try to smooth this thing out? Is there some alternate design you'd recommend I try?

Edit: Some context: the crawl is part of a digital signage application (played from a standalone Flash projector -- no web browser) that does stuff elsewhere on the screen, including video playback and rendering text and images. It definitely gets choppier during video playback, but it's never as smooth as I'd like it to be.