I now deal with this issue very frequently and this info may be helpful in understanding the options:
It is a good practice to convert AI text to vectors to avoid font issues. The downside is that, when receiving artwork from designers only trained in using AI for print work, they typically don’t understand (and refuse to accept) the methods necessary to make AI artwork useful for other purposes (like motion graphics). So, all of the artwork will often be inside of one layer and/or randomly scattered among a bunch of layers all with names like “layer 1, layer 2”, which makes animating the letters of a word very difficult. The only solutions I’m aware of are to have all motion graphics designed by mograph designers, require/convince print designers who contribute artwork to do the following two things or do these things yourself with all the print artwork you receive:
[1] put every piece of artwork you might need to animate on it’s own layer in AI (including individual letters of text)
[2] spend an extra few seconds to give every AI layer a descriptive name since each of those seconds avoids wasted minutes or more in AE
I’m still on CS3 so, unless this has changed in CS4, AE text animations only work with text layers. They can be used with Photoshop text layers by applying AE’s “convert to editable text” function, but I’m almost certain that doesn’t work with AI layers (99% certain … just didn’t double check before writing this). However, I consider having to convert PS text inside AE a sign that I should have created the text in AE in the first place since converting often creates a whole new set of issues with trying to retain all the stylization done in PS when it would’ve been easier to just do the same things in AE from the start.
So, that was the long answer. The short answer is, if there’s an easier way to animate AI text in AE, I’d love to hear it too!