Yes Servlets are the way to go. You will have a buffer between your EJBs and the PDA. that way you can take whatever you get from the EJB and make it such that the transfer to the PDa is the smallest it can be, thereby speeding your application.
Servlets can access EJBs very nicely, that is why in their web.xml files they have tags for EJB's.
When I say Servlets I also am including
JSP in there.
Unfortunately, it looks like you can't use RMI to access classes outside the PDA, that is why you can't access EJBs directly.
Mark