Capture Header Value For Property Transfer

Hi,

I need to transfer the value of a custom header from a response to pass onto a subsequent GET request.

I found the following (which is very helpful) but I'm a little stuck

My test hierarchy is as follows:

POST (payload embedded on request)
GroovyScript (to grab the 'originalFilename' header from POST response)
Properties (to hold the 'originalFilename' property value)
GET (to retrieve a record based on the 'originalFilename' property value)

the other page indicates the following groovy can be used to extract a header value:

//Takes one of the elements of the response Header
def value = testRunner.testCase.testSteps["POST"].testRequest.response.responseHeaders["originalFilename"]

//Read this value into a parameter
def groovyUtils = new com.eviware.soapui.support.GroovyUtils( context )
groovyUtils.setPropertyValue("Properties", "originalFilename", value.toString())

HOWEVER - the property value is returned within square brackets [] which the other page indicates is cos its an 'array to string'.

It suggests altering the 

groovyUtils.setPropertyValue("Properties", "originalFilename", value.toString())


to groovyUtils.setPropertyValue("Properties", "originalFilename", cookie_vals.[0])

HOWEVER - the above doesn't work.

Does anyone know how I can alter the groovy slightly so the value is not returned within square brackets?

thanks to all!

richie