I'm going to make some assumptions here.... that you're using Invigorator for AE and that you're using text convered to outlines in Illustrator. If so, perhaps the letters are all part of the same grouped object in Illustrator? If so, ungroup them there or use the check box when you import them into Invigorator.
I could be way off base. Please describe the situation a little more and we could give some more specific advice.
I've now ungrouped the letters in Illustrator and in fact I can move and rotate them seperately. However I just didnt find out how to set keyframes because I cant do it in the menu (or at least I dont find the option) and I still dont know how to assign characters to a set.
I hope you can understand my english because I've only learned it for 8 years in school :]