How do i update my Speedstream 4100 modem?

I was looking at my wireless settings using the 192.168.0.1 thingy and i went to advance and it said update modem, ive updated my router too many times but i never updated my modem in a year. It tells me to dowload the latest version from my service provider (is that AOL or SBC?) anyway i googled, yahooed, everything and i cant find an update. So where do i go?How do i update my Speedstream 4100 modem?
I was doing a google search and found this website:

http://subscriber.communications.siemens.com/subscriber_networks/upg-4100.shtml



I haven't tried it yet (not sure if I really want to - my modem seems to be okay). Anyhow, the update is from 2005 and is to v53. I'm currently on v48.