Defining an AS400 connection

In our shop, we are doing some experiments with Java. We access the 
iSeries database with JDBC. When our pilot application is started, a 
JDBC-connection is established with the statement "connection = 
DriverManager.getConnection("jdbc:as400://systemname")". A pop-up window 
is displayed, allowing the user to log on. So far, so good. Now, in the 
application, we have to call an RPG service program. We plan to use the 
class ServiceProgramCall from the AS/400 Toolbox for Java. The methods of 
this class require an instantiation of the class AS400. Of course, we 
don't want the user to have to log on two times, once for creating the 
JDBC-connection, and once for creating the AS400-connection. Is it 
possible to create the AS400-connection 'in the background', making use of 
the fact that a JDBC-connection has already been established?

Ewout