Refresh Cache of JCO/SAP

Hello,

I use JCO to connect to SAP in order to get some information

about leave by calling a BAPI.

Everything works fine, but the information - i get back - are always the same as for the first time.

F.e. First time gathering information for an employee No. 00002

gives the correct result, second query gives the same information,

even if meanwhile new records in SAP have been generated.

Only when connecting to SAP with another userid or complete

restart of SAP, the updated information are available.

Is there a CACHE in JCO/SAP and does anybody know, how

to refresh this CACHE ?

Plz help

Christian