I don't think so, and I tried it on a dev instance Tableau 10 server too and didn't see any dual axis capability here. It does appear there is already an idea on this one that can be voted up.
Also, this thread belongs in the main forum, I will move it.
In Server you can make a basic dual axis graph by using the "Show Me" tool in the top right corner of your worksheet and selecting dual axis graph.
By default this will give you a bar chart with a line on a dual axis. You can then change mark types, colours and sizes etc. using the marks card. One drawback of dual axes in Tableau Server is that because you cannot edit axes in Server, you cannot synchronize them either.