The original VirtualDub Deshaker plugin has improved since the "New Deshaker" work was done. You might try just using it externally in VirtualDub then rendering an intermediate file to bring back into Vegas.
We are using Vegas 64 - it is a script and works fine in Vegas 11-64bit. It does use the 32 bit version of VirtualDub. Have a look at my post here (it is the last one) for some description of the changes in the latest version and installing for Vegas (32 or 64bit).