I use a dial up modem.
A while back, a new dependency was added, "dialog.tcz." You need this to set up a connection.
I think pppsetup only works for a modem connected to a serial port. If anyone has it working on an internal modem or usb modem, let us know what you did.
I actually made an extension containing my settings some time ago. When I update, I just copy my extension. I need a .dep file for my extension, to make it work. This contains "bash.tcz." I also have my extension in On Boot.