@ysageev we're fisrt making the transfer from vmware work through an HTTP link in xo-cli. After this we'll do a UX, allowing a user to migrate from XO , it will probably be a three steps form : connect to an host, choose which VM(s) to migrate , transfer progress
Then, depending on the priority , we may make other transport ( for example if you mounted the VMFS datastore in XO, copied files locally or through SSH)
By the way, we fixed a timeout bug in xo-server, that was cutting the vmdk/ova import around the 5mn mark, you may retry the old method