How should a disciple of the Buddha with great samadhi verify that rebirth occurs after physical death?

I asked my teacher how somebody should see for themselves that rebirth occurs, he (a Theravadin monastic) said that with great samadhi one should watch the twelve nidanas (the process of dependant co-arising) to see the eleventh nidana (becoming leads to birth). I can accept that if one watches the nidanas then one would see that becoming leads to birth. However, seeing birth occurring during our (biological) life is separate from concluding that (re)birth occurs after physical death. I think that the most simple way to put this is that the process of becoming leading to birth is not dependent on the body. If one can see the eleventh nidana then how would they confirm that the eleventh nidana does not require form? Perhaps I am on the wrong track entirely and the proper action is to watch some other process to see that the mind (instead of just the nidanas) does not require a body to sustain it.