Blackberry 7270 and asterisk

Hi all,
I’m trying to get Blackberry 7270 connect to my asterisk box.
7270 can communicate to PC via Blackberry Desktop management (I don’t have Blackberry Enterprise Server) for upload and download programs. Wifi is Ok as I could install Opera mini and browse the web. However the VoIP setting in the Options doesn’t work. asterisk -rvvvv doesn’t show the phone register in and when I make a call from the Phone program (Blackberry apps) it wait for 30sec and say “No service currently available”.
On my network there are currently IP phones and softphones and Wifi phones (UTStarcom), all of them work ok.
Has anyone succeeded in getting 7270 work with asterisk? Please show us how.
Thank you very much,