Testing a REST web service using the POST method -- I want to paramaterize from a CSV file

There are many test tools (JMeter, SoapUI, etc...) that will allow you to parameterize your test cases so you can do many tests with just 1 CSV file. But these are for tests using the GET method. I need to test using the POST method with a lengthy piece of XML being sent for each request. The tools I have researched expect a separate XML file to be created for each test case. Is there any tool available where I can just use 1 request template file (maybe an XSD) and 1 CSV file? This would allow me to manage hundreds of test cases with just two files (rather than having to manage hundreds of individual files).