If you're playing DSA 4.1 in German you could check out https://www.helden-software.de/ for character management. It seems alright, even though I'm no fan of DSA and only played a oneshot – our GM seemed to like it though.
For campaign/story log-keeping I'd just suggest that you would use some kind of text-files and that's it. If kept organized it should work out well.
Text files would be difficult to use with two persons.
And of course Helden Software :)
Maybe try Google Docs, or something http://etherpad.org/ for live collaboration?
Or just upload it to a cloud service like Dropbox, Google Drive, etc. and give your friends access to download and change the files, if you are certain enough that people can behave themselves (i.e. asking before editing), so that there are no conflicts.