Hello Smith,
>>we are using PI 7.1 . i cannot use AXIS
You can definitely use Axis as Iñaki Vila mentioned. The only affordability is download/collect the JAR files and deploy it in the server 
.. We can definitely get the files, I was wondering if you could check if XML is an option to avoid converting CSV to XML back again. If XML is not an option, then I believe we can use the MessageTransformBean in the AXIS adapter to convert the CSV to XML. Again I believe it's possible, haven't tried myself. But definitely tried the parameters on other channels other than JMS adapters in the past.
How To...Content conversion module with J2EE JMS adapter - Process Integration - SCN Wiki
Thanks!