Close Abap session of a stateful web service from Java application

Hi,

we
need use a stateful web service developed in ABAP starting from a BAPI for a
distributed transaction (transaction ivolving SAP a non SAP System).

At
the end of the distributed transaction we need to close the session on SAP.

We
are trying to use the SOAP message below sent to web dispatcher:

<soap-env:Envelope
xmlns:soap-env="http://schemas.xmlsoap

.org/soap/envelope/">

<soap-env:Header>

<n0:Session

xmlns:n0="http://www.sap.

com/webas/630/soap/features/session/">

<enableSession>false</enableSession>

</n0:Session>

</soap-env:Header>

<soap-env:Body/>

</soap-env:Envelope>

but
it doesn't work.

Have
you any idea about this issue?