you cannot. HTML doesn't support array/dict style thing, only flat names. That is, you need to name them when generating the HTML with something like a_1,a_2 then do the reverse thing when received the form data.
I think JSON is a better solution for this. Just have js that loop through the table tree(on submit) and grab the contents then construct a using MochiKit's JSONSerialize and put that into some "textarea" field. On the receiving end, unpack them back into list/dict. This way, the fields in individual rows don't need unique id/name.
