Thank you for the fast answer, unfortunately I don't want to scale my object depending on the viewport. The scene is only one part of my creation and the main thing has to keep its aspect ratio so there's no way to use viewport based units.
I found another animation library... It's working how I want it so I guess we done here. Just crazy that only cause it is using matrix (what is not the only way to animate) some units are disallowed completely. So if you want my honest feedback, for a library so heavy (even the lite version without ease, timeline and css3?!) there's no way you can't fit unit detection and if em just don't use matrix. Or at least a plugin or something...