RPG to Java-based Services

We are in the process of implementing a new policy admin system under
Insurance Application Architecture (IAA) and some third party software
components we've purchased and can no longer directly access a database
file to get the data we need for legacy systems. This is a rule by the
vendor - all data within their components must be retrieved via their Java
based services - no direct access or SQL. However, all of our back-end
systems (Billing, Claims, etc) are written in RPG and Synon RPG. We need
to integrate this new policy admin system with the old back-end systems
and do not have any experience in the techniques or technical
implementation options to make this happen.

My job is to figure out how to do this - have our legacy RPG/Synon based
applications access their Java based services - what methods are possible,
pros/cons, performance implications, etc. These "services" can be exposed
as either web services (SOAP/HTTP) or EJB2 RMI. I believe at the moment
they are EJB's and are remote - they will not reside on the same physical
box as the RPG code. The platforms of each box more than likely will be
different: Our legacy RPG code is on an iSeries, and the Java based
services will be deployed within Websphere Application Server on Windows,
AIX or Linux. More often than not, we'll need to send in parameters, and
be able to get back all of the relevant data we're looking for.

Any ideas or experiences?
Erin L Strobel
Information Services - Programmer
Church Mutual Insurance
1-800-554-2642 Ext. 4947