I CAN'T CHANGE ONLY THE VALUE OF ATTRIB "value" (my first idea ), because this's only an exaple! In real my nodes are full of sub-nodes, then I must move sub and sub and sub nodes, too.
My onlyone solution found is:
1) read the old xml file
2) in dom-tree insert a my tag with progressive number
3) insert new tags (in append...) and mark it with position number needed.