I've found this cable that seems to be just what we need to charge our n900. I purchased it based on the "bad" reviews which in our case is exactly what we need. So charge only, no sync.

http://www.bestbuy.com/site/Rocketfi...1MRA&cp=1&lp=1

I have a zagsparqq that only worked occasionally with the provided cable, with this cable it worked right away. You can find it on ebay for much cheaper. Hope this helps.