Having looked at the source of the Vaadin Eclipse plugin, it always checks online to see if there are to get the downloadable list of Vaadin Versions.
(See VaadinProjectFirstPage, VaadinVersionComposite and DownloadManager )
It appears that it's not currently possible to create a new Vaadin project using the Wizard within Eclipse Plugin without access to the internet - even if you've already downloaded the appropriate jars using Ivy.
I can see that this could be problematic - and I would suggest that you report this on the Vaadin Forum, where the plugin developers may consider fixing this as a bug.