Order by with XSL

Hi, thank you for the reply, i have a similar XML, and i would like to order
for ammlegal. In the stylesheet, with FO, i make a table, with three
columns. Every row is a factory, and then with company address, ammlegal and
resarea. How i can order my table with ammlegal?
Thank you...
I hope you can help me...
Regards
        Gianni
------
<elenco>
	<title>Gerarchia GPI e HIT</title>
	<ditta company_name="sssss" Address="xxxxxx" Phone="1111111" City="eeeee">
		<ammlegal>FFFFFFF</ammlegal>
		<resarea>AAAAAAAA</resarea>

	</ditta>
	<ditta company_name="jjkhkj" Address="jkj" Phone="3329438" City="uihjh">
		<ammlegal>BBBBBBB</ammlegal>
		<resarea>RRRRRRRRR</resarea>

	</ditta>
</ditta>