TreeView Sort Problem

Hi there,

I got a little problem. I want to sort items of my treeview. Alphasort
returns following result for instance.....

button1
button11
button2
button6
test1
test2

but I would need it sorted the following way.....how can I do that?

button1
button2
button6
button11
test1
test2

Does anybody know what to do to sort it in this way?

Regards,
 - Tassilo -