I am working with xsl. i want to store a value in the variable.

xml Source looks like the below one
[code=xml]
<?xml version="1.0" encoding="UTF-8" ?>
<getTradingInst allmentHistoryR esponse xmlns="http://www.openuri.org/">
<getTradingInst allmentHistoryR esult>
<InstallmentDet ails>
<installmentNo> 1</installmentNo>...