I don't know enough about TPTP to help your here, but I would just go and see their docs/faqs about debugging any other java application....nothing mysterious here in respect to JBoss AFAIK.
Regarding WTP server definitions then we really would like to use it but it still is a work in progress and there are some limitations in WTP we haven't found a good solution for yet. (e.g. we find it troublesome that you are required to have physical seperate projects when using both web and ejb modules)
so in short...we are working on it and any contribution in this respect is very welcome.