I went through the process at -

http://spvunlock.rd.francetelecom.com/

I loaded Resco Explorer and the registry editor at (nice bit of kit) -

http://www.resco.net/smartphone/explorer/downloads.asp

I then set the 2 registry keys in hklm\security\policies\policies on the phone

to

00001001 value= 1
00001005 value=40

Rebooted the phone and hey presto...

I am pleased to report Live Search Mobile now installs - not sure if the above is related or not,  but it certainly is working,

Next mission, is to get Visual Studio 2005 able to debug on the device.   I'm currently getting the following

Error 2 The device security configuration disallowed the connection. Ensure that you have the appropriate certificates on your device for development. Review your SDK documentation for proper security settings for connecting to this device. Device Connectivity Component

 Will keep you posted.