You will not be able to make a dial-up connection using PAN and the "Internet Sharing" app (IntShrUI.exe). PAN is a different type of Bluetooth profile than DUN, and is seen differently by the paired computer. If you re-pair your computer with the phone, you should see a type of connection called "Personal Area Network", or perhaps "Network Access Point". This is what is enabled by IntShrUI.exe. I can't verify this, as I don't have a Windows PC with Bluetooth (Macs don't support Bluetooth PAN), but that is how it is SUPPOSED to work.
When using the BT DUN profile, your PC sees the phone as a modem device (the DUN profile builds on the BT Serial profile). When the PC sees a modem device, it is pretty easy to set it up to dial out for internet access through Windows' Dial-up Networking support.
When using PAN, the PC no longer sees a modem, or serial device, at all. The BT PAN profile behaves like an actual network connection, similar to a wireless or ethernet card. After re-pairing the phone and PC, you should see a new network adapter for the BT PAN profile (IntShrUI.exe may need to be running, I'm not sure). Simply configure and use that network device to connect to the internet, no dial-up configuration needed.
Again, I haven't seen any of this in person, as I don't have a PC with Bluetooth. My explanation is simply from a deep understanding of how it works. If someone can test this and post the results, I would really appreciate it!
