Seems to be the start of a solution here http://support.advancedcustomfields.com/forums/topic/frontend-form-post-via-ajax/
This one seems to have more information and even some helpful guidance from our benefactor. http://support.advancedcustomfields.com/forums/topic/using-acf-form-in-ajax-call/
Here’s one I contributed to that appears to ave been a help http://supp ort.advancedcustomfields.com/forums/topic/use-update_field-with-ajax/
hope some of this helps
