I have learned that vault limits the use of inventor if the bandwidth between the local PC and the vault server is small.
Inventor becomes almost un-useable if the bandwidth are lower than 50 MBit/sec. This means that it is impossible to work via mobilephone, even if you have prepared your work by downloading the files....
The system requires some kind of pending between the vault server and inventor.
Autodesk should inform users about these limitations.