As far as I remember, that should be indeed possible. But keep in mind that the gifts that follow the supersponsor upgrade as thanks for you generous contribution, might be limited as these are ordered some time beforehand.
Thank you for your willingness to support the convention
![Grin ;D](https://forum.eurofurence.org/Smileys/default/grin.gif)
Edit: You can also try to contact the reg. department via "reg@eurofurence(dott)org" But they might be busy this last week, but worth a shot