extra initialization command option grayed out / not working for bluetooth modem

hi

I am trying to set up bluetooth modem so that I can connect to internet from my mobile using bluetooth but it appears I can't do this because the place where I need to specify extra initialization command (I found I need to do it to use proper APN ) .
I even updated my drivers but nothing helped. Still the extra initialization command section is not working. I accessed it from

control panel --> phone and modem --> choosed my modem --> its properties and then in advanced settings.

Please help to solve this issue.