Stored Procedure job date when invoked from WebSphere

We use WebSphere Application Server 5.1 and access data in DB2/400 over JDBC using the toolbox driver in jt400.
There are instances where we call stored procedures (RPG) in DB2/400.  These stored procedures make use of Job Date in their processing.  The SQL and stored procedures run in the QZDASOINIT job.  

Ok the problem is that this job date is the date the job was started, so as we pass midnight, the job date is incorrect.  So, we can end those jobs at midnight and new ones will be started automatically as WebSphere needs them (they are prestart jobs).

Unfortunately, the job date of the new jobs is not the date that QZDASOINIT is started, it is the date that WebSphere is started.  It "inherits" the start date from WebSphere.  Note also that WebSphere and/or OS/400 take care of starting extra QZDASOINIT jobs as required - I cannot manage the starting of these jobs myself.

So, to get the right job date, we must
Before midnight
 - stop the QZDASOINIT jobs
 - stop WebSphere
After midnight
 - start WebSphere
 - When WebSphere  tries to use JDBC, QZDASOINIT jobs are started with the correct job date

Is there an alternative solution here that means I do not need to restart WebSphere as I want to run 24x7 ?

Thanks
Andrew