Thanks for the replies.

I was guessing already that it will be a big hazzle to get a 3rd party HD mounted, but I was just wondering if there are musicians out there who have succesfuly done it.

I think that for me a Solton HD is also the best option.
George, what a pitty, but I already have a X1 without HD. So I will have to get the original HD without any extras.
Is there a way to maybe send some stuff of the HD over the Internet, or would that be a very difficuilt and (most of all) illegal act?

Marc