Replace request content using RequestFilter.filterRequest does not work

I want to send urlencoded request, to achive that I am using following code in RequestFilter.filterRequest

def requestHeaders = request.getRequestHeaders()
def contentType = requestHeaders.get("Content-Type")[0].trim().toLowerCase()
def reqContent = context.requestContent

if (contentType=="application/x-www-form-urlencoded" && reqContent){
	reqContent = java.net.URLEncoder.encode(reqContent.replaceAll('\t', '    ').replaceAll('\r\n|\n', ''), 
														    java.nio.charset.StandardCharsets.UTF_8.toString())
	context.requestContent = "=$reqContent".toString()
}

But It doesn't send URLEncoded request. According to http://blog.smartbear.com/soapui/soapui-pro-holiday-goodies-event-handlers-and-jdbc-connections/ article, it should work. Am I missing something?

I don't want to use SubmitListener.beforeSubmit event with request.setRequestContent as It changes request content in the test and next time it becomes unreadable for anyone.

Any Suggestion folks?

Thanks,

Ritesh