all your replica was incorrect! - like everything, about NWDI, about being 'tightly' integrated and about not being able to run ISA /Biller Direct on Tomcat.
(this is the only bloody way I work with something like ISA, so I can guarantee you it works, still works and will pretty much work in future because nothing will change on those dead SAP products)
and, it's simple, it's really simple.. it doesn't take several months, because already took some people some time - and knowledge was shared - so it's more like hours instead of months we're talking here.