ITSmobile - SET CURSOR not working

We are using ITSmobile and have issues with SET CURSOR. This works in SAPGUI (of course) and on a PC in IE (but not in Firefox). On a mobile device (Symbol MC9090, WM5) it does not work with any of the browsers we tried (Pocket IE, Naurtech, WaveLink TelnetCE). In all browsers no input field is active...

We are using SAP ERP 6.0 (SAPKB70012 - yeah, I know, not up to date).

I found several threads here with the same issue bit no solution...

Thanks!

Ingo