I would start in control panel>internet options, pick the connection tab, and click the radio button for 'always dial my default connection'. Then OK out.
Back in control panel>network conntections, right click on your Dial up BB modem, pick properties, and then pick the 'options' tab from teh new window. Untick 'prompt for name and password etc' and also untick 'prompt for phone number'.
In theory, now, whenever any program needs an internet connection the PC will start up the modem, and the modem will automatically connect up.