Bluetooth Dial-Up Networking using Blueman

I want to configure a dial up network connection via bluetooth to my phone in order to access the internet.

I use Lubuntu 12.04 (Ubuntu with LXDE) which has the Network Manager Applet and Blueman applet installed. I guess these are the same tools than on an Ubuntu installation, hence I ask my question on this site.

My phone is a Sony Ericsson W810i, my laptop is a Lenovo S10-2, my mobile phone provider is o2 Germany.

I scanned for my mobile phone using the Blueman applet. I connected the dial-up network via the context menu -> Serial Ports -> Dial-up Networking. A notification bubble says that the connection is available on the interface named ppp0.

ipconfig is telling something different: There is no ppp0 or something similar. I only see my eth0 (wired ethernet), eth1 (wifi) and lo interfaces. Of course, I can't ping google.com as the interface really seems to be not present at all.

When the dial-up network is being connected, my mobile phone says that it connects to the internet. Afterwards, I see the active connection on the phone's screen. When successfully connecting with the phone using another computer, it behaves exactly the same, so I guess that the phone isn't the problem.

I don't know if I configured the Dial-Up correctly. I use the phone number *99# which is very common on most mobile ISPs. I use the APN which my ISP is telling me to use. (I can't find the number on their support page, so I just use the default value *99#.) My mobile ISP is o2 Germany.

There are How-Tos out there which use the Network Manager Applet to setup a bluetooth dial-up connection, but I can't see any bluetooth devices in the context menu as on the screenshots in those How-Tos.

Do you have any suggestions what might be wrong / what I should try?

EDIT:

When choosing "Network Access Point" in the device's context menu instead of Serial Ports -> Dial-Up Networking, an interface bnep0 appears. However, neither an IPv4 address is assigned for that interface (but IPv6), nor the phone connects to the internet. Am I missing something? Can I connect to the internet after setting up this network connection?