Jornada 720 and bluetooth with HTC P3600 HELP

Hi,
I stumbled upon a real puzzle.
I have an HTC P3600 with WM5 and I need to use it as bluetooth modem with my Jornada 720 (but also with NEC 900c, the problem is the same).

So, I find it and pair it but when Jornada lists all services available on HTC it says everything but DUN.

In this way I am not able to use dun connection.

A few days ago my HTC has wm6 and I could use it, but now after changing it I can't.

Moreover, there is a strange thing that happen when searching for device. In device searc tab there are different options. If use the one saying "any bletooth capable device" or "another pda or computer" I find it without problem, but if I select "phone cabale device" it is not found. I can't work out this problem.

Can anyone help, please?