I am in the same situation (initial assessment from my tax person is I owed monies for 2008 and 2009) as I am leaving in a few months back to the UK. When I asked my tax person I was told I have to wait for official confirmation from the local authorities which takes up to eighteen months from submission. Then the company who do your taxes will contact you and ask how to deposit the funds - I'm assuming you will then need to keep open a Swiss bank account until this is fully closed.