Domain mapping dont work with umlaut Domains

Hi,

i use your domain mapping tool. But it dont work with german umlauts. so we have in some words äöü (aou).

http://www.example-mün.de/

Dont work.

but these works http://example-test.de/

When I logged in as a administrator and I visite http://www.example-mün.de/ => wp will create a new site:

in the domain mapping tool I added example-mün.de

or should i add the punycode of the domain? But could you tell me what is the punycode ?