Joakim,
If the sword is shipped in a saya, without a tsuka and the mekugi through the tsuka and nakago, the saya won't protect the blade; it stands a good chance of seriously damaging the blade. If the package were dropped the blade could crash down inside the saya and shatter its kissaki (point) in the botom of the saya.
If it's not to late to stop the shipment, here is how to properly pack the blade and saya. Wrap the scabbard in a few layers of newspaper and tape. Tightly wrap the blade all over in quite a few layers of newspaper, making sure that the paper is folded over both ends, and tape shut. Now, securely tape the blade bundle to the scabbard bundle, with the point of the blade above the bottom of the scabbard, and it's ready to pack and ship.
To answer your question, you need to have a shira-saya made for the blade, and a habaki also if there is none. The chances of finding one to fit the blade are astronomically small. I could suggest someone in the States; maybe someone in Europe could suggest someone there (closer to Stockholm).
I know you've spent your budget but now you have a responsibility. It is your duty to see that the blade isn't damaged; it needs a properly made shira-saya and habaki.
Grey