how to sort xml file in UNIX

We have XML file, (Date: DD/MM/YY)

<ABT><pid>101</pid><date>10/12/13</date><name>AAA</name></ABT>
<ABT><pid>102</pid><date>11/12/13</date><name>BBB</name></ABT>
<ABT><pid>101</pid><date>09/12/13</date><name>AAA</name></ABT>
<ABT><pid>102</pid><date>24/12/13</date><name>BBB</name></ABT>
<JRE><pid>101</pid><date>01/12/13</date><name>AAA</name></JRE> 
<JRE><pid>102</pid><date>02/12/13</date><name>BBB</name></JRE>

output should be as

<JRE><pid>101</pid><date>01/12/13</date><name>AAA</name></JRE>
<ABT><pid>101</pid><date>09/12/13</date><name>AAA</name></ABT>
<ABT><pid>101</pid><date>10/12/13</date><name>AAA</name></ABT>
<JRE><pid>102</pid><date>02/12/13</date><name>BBB</name></JRE>
<ABT><pid>102</pid><date>11/12/13</date><name>BBB</name></ABT>
<ABT><pid>102</pid><date>24/12/13</date><name>BBB</name></ABT>

How to sort this file based on <pid>, <date>.