Microsoft Teredo server and 2001::/32

[Anssi Porttikivi]

Based on http://www.sixxs.net/tools/grh/lg/?find=2001::/32 (yes,
2001::/32 is routable at least somewhere)and
http://psg.com/lists/v6ops/v6ops.2006/msg00064.html (yes, Windows can
use it)I try to get global IPv6 connectivity from my laptop (XP SP2).
The Wikipedia Teredo article confirms that there would be a public,
globally available relay for 2001::/32 (in Italy)?

I am using the Microsoft Teredo server but I can get it "qualified",
meaning the Teredo configuration finished. (It does work without the
registry hack there, for old 3ffe:831f::/32) I tried also
teredo.remlab.net but with no better success.

Does the Microsoft Teredo server support 2001::/32?. Generally, can the
Teredo protocol client choose the prefix

a) always
b) when the server supports them 
c) or does the server always choose it?

To me it would seem that the server does not care which prefixes I use.
Only the relays care, and inidrectly the end-point using the relays care
about their reachability. So the client should be able to freely choose
a prefix? Why can't I with this configuration?

Yours,
Anssi.Porttikivi at teleware.fi