Jelf12,
You should be careful about providing too much information in the CSRT, I usually recommend that people just rely on the caption text for checkboxes -- if the information is sufficient for sighted users, then in combination with the information provided to the assistive technology via our accessibility API in Adobe Reader the information should be sufficient for non-sighted users.
For example, if you have a checkbox that has a caption that is "Please send me information about new offers", that would be fine for screen reader users because when they land on the checkbox they will hear "please send me information about new offers, checkbox checked" and if they uncheck it (you can assume that how to toggle a checkbox is common knowledge so don't need to convey this information) they will hear "Unchecked". If the user tabs away and tabs back they will hear the full explanation again, except with the changed state reported.
It is tempting to overdo it, but for most checkboxes all you need to do is make sure that the screen reader precedence is set to "Caption" and move on.
AWK