Transfer gamertag from one microsoft account to another

Hi,

I have a gamertag associated with my microsoft hotmail email account which belongs to my son. I was never an Xbox gamer, so I let my son create and use a gamertag under my account when he was young.

Now he is old enough to have his own email account. So I would like to transfer the gamertag - along with all purchases and game-playing history to his own account.

There are multiple issues with the current setup:

- the gamertag is associated with my name, not his

- since he logs with my account, it is a shared password

How can I go about doing this?

Thanks,

Ashutosh

:)