overriding sap portal log off in portal 7.3

Hi All,

my scenario is as follows:

once user log off from portal, I need to put back all the claimed tasks by the user.

so I implemented a rest service to put back the tasks using BPM APIs.

Now I need to call this rest service before portal logoff is invoked.

I am following the link Sap portal 7.30 - change portal masthead. Libraries that you need to start customization. - Netweaver Technology - SCN W…

to override portal code.

we took the com.sap.portal.navigation.afp.masthead.war from server and decompiled the MastHead.class file.

but there I did not find any logoff logic.

can anyone please guide us to where we have to include our rest call to put back all the tasks before portal log off happens?

Thanks

-Trim