Currently, the only way to build new animations for Vizard avatars is to use 3DMax Character Studio. There's a free plug-in available that exports from 3DMax in cfg format which can then be used in Vizard. So yes, that is a good idea and if you're familiar with CS already you'll find this very straightforward.
Here's a 3rd party tutorial you can look at to see the steps involved in building and exporting cfg compatible avatars:
Exporting Cal3D avatars from 3DMax
Hope that helps. Don't hesitate to ask further questions.