ITS - logoff without closing web browser ???

Hi,

I run Internet Transaction Server (WEB GUI) on SAP ERP ECC 6.0, EHP 6.0 (only ABAP stack). I have a lot of SAP clients, and if I click button LOGOFF (on ITS), and try to logon to ITS again (without closing web browser), system log me automaticly to the same client, without username and password. What can I do if I`d like to logon to the other client without closing web browser, only way  it`s closing web broweser ? Or can I setting some SAP parameters ?

Thanks.

BR

T.