Probably only the hard way by using multiple layers and animating them individually...
It seems like there was a motion math script for this but any copies I have of MM scripts are long gone. That's the only way I know of generating automatic animations in AE 4.1.
This is the first time I've realized that you were using 4.1. I thought you were using CS4 when I kept pointing you to Expressions. There may be a few MM scripts still floating around the web but that kind of code is more than 10 years old and I'm not sure that the text engine in 4.1 supports that kind of access.
Yes, I'm using AE 4.1, per my explanation in my other posts about the timecode effect and codecs.
Since there is a built-in random number generator in AE 4.1 that is part of the Numbers Effect, I thought there may still be an after market Effect, plug-in or mm script for a random text generator.
I've been searching the web, but its a big place.